United offers Economy Plus seats with up to six inches more legroom than standard economy.
United's Priority Boarding puts you in Zone 2, ensuring overhead bin space for your carry-on.

Planning a trip from Denver to Knoxville? KAYAK’s data-powered insights will help you find cheap flights. Learn the best time to fly, how early to book your ticket, and other tips to secure great prices.
| Low season | January |
|---|---|
| High season | October |
| Cheapest flight | $51 |
Direct departures
Denver Intl to Knoxville McGhee Tyson
Monday
United Airlines, Frontier
United Airlines, Frontier
Tuesday
Allegiant Air, Frontier, United Airlines
Allegiant Air, Frontier, +1 more
Wednesday
United Airlines, Allegiant Air
United Airlines, Allegiant Air
Thursday
Allegiant Air, Frontier, United Airlines
Allegiant Air, Frontier, +1 more
Friday
Frontier, United Airlines
Frontier, United Airlines
Saturday
Allegiant Air, Frontier, United Airlines
Allegiant Air, Frontier, +1 more
Sunday
Allegiant Air, Frontier, United Airlines
Allegiant Air, Frontier, +1 more
Direct returns
Knoxville McGhee Tyson to Denver Intl
Monday
United Airlines, Frontier
United Airlines, Frontier
Tuesday
Allegiant Air, Frontier, United Airlines
Allegiant Air, Frontier, +1 more
Wednesday
United Airlines, Allegiant Air
United Airlines, Allegiant Air
Thursday
Allegiant Air, Frontier, United Airlines
Allegiant Air, Frontier, +1 more
Friday
Frontier, United Airlines
Frontier, United Airlines
Saturday
Allegiant Air, Frontier, United Airlines
Allegiant Air, Frontier, +1 more
Sunday
Allegiant Air, Frontier, United Airlines
Allegiant Air, Frontier, +1 more
Staff were friendly and happy. Delta could make sure passengers that don't have the app know of changes. Without Kayak I would not have known about the change of gate or the delay. Kayak was faster to notify me.
Staff were friendly and happy. Delta could make sure passengers that don't have the app know of changes. Without Kayak I would not have known about the change of gate or the delay. Kayak was faster to notify me.
They ended up paying for the bag twice, but the counter wouldn't take my baggage receipt. Left it to me to resolve. Not sure how to resolve the issue.
The customer service before board was very rude and when I expressed my concerns about making the connecting flight she laughed and told me I bought the wrong ticket. I explained once it showed the flight was delayed it no longer let me change seats or anything. I was trying to upgrade to make sure I would get to the next gate on time.
Non stop on long haul is the way to go. Great experience
The flight used a B767 with a very old interior from before 2014. The entertainment system did not work at all during the flight despite attempts to reset the system. It was like they flew this route just to be competitive.
They changed planes and the new plane couldn’t carry enough fuel to fly across the country so we had to stop in Kansas City to refuel. Flight was delayed .
Flight was too crowded and seats are too small, especially since passengrs are getting larger. Having a middle seat is ALWAYS tough! Woman on my left was large & kept creeping in to my space. Flight personnel were great! Have more savory rather than sweet snacks please.
Flight was crowded and the woman sitting on my left was large & kept crouching in to my space. You need bigger seats or smaller passengers to fit into the seats you DO have! Snack were OK. Would appreciate if airlines had more savory rather than sweet snacks, thank you!
Delayed flight (1hour) plus a long layover after an overnight flight with no backup plane available.
We were delayed, which I think had to do with air traffic control. Otherwise, everything was great.
Crew seemed a bit cranky. No seatback screens. But boarding was efficient and on time and we arrived early.
See previous note about the passenger in Denver who threw my husband's bag out of the overhead bin in order to maker room for his own. And the flight attendant back up the new passenger.
Terrible. They wouldn't allow me on my flight on the 14th..
Impressed with the service despite turbulence because of the weather. Both flights arrived before their scheduled times.
Great experience…left a bit behind schedule but made up fir that in the air and landed 10 minutes early 😁
Electric plugs didn't work. Entertainment system wasn't working
The design of the light switch on the arm rest is ridiculous.
The gate attendant let me walk right by her with a bag too big for the overhead compartment
Overall, it was a good experience. Boarding was good and there was plenty of overhead bin space for everyone’s carryons (even when we boarded toward the end). Only improvement would be to offer trash service more regularly.
David went above and beyond to make our flight the best that it could be
The flight attendant, a black woman with curly hair who sat near Row 21, was wonderful and kind.
It was good..clean, comfy seat. Friendly warm welcoming crew. Was able to check my cabin luggage at the gate which I was able to pickup in a decent time from baggage claim. The app gave all updates from delays to baggage claim info. Overall smooth flight.
Flight was delayed leaving Dallas. Arrived about 2 hours later than scheduled.
Flight delayed and missed connection. Rescheduled flight cancelled after 6 hrs wait. Rerouted thru ORD, flight cancelled, overnight stay in ORD. Still in the air on new flight!
We are too tired and frustrated to comment politely at this point
Terrible. Our luggage was delayed and couldn’t be delivered for several days. We got bad information from the airline agents at baggage claim. We had to pick up our car so we wouldn’t be charged for an extra day. We got lost in the maze of airport parking. The baggage claim agents didn’t offer us any compensation for our extra time and expense. We are tired, hungry and very frustrated.
The flight was flawless and we even arrived between 20 and 25 minutes early!
The only thing to like was that we eventually got to our destination
Delayed delayed delayed and no offer for food or vouchers
Typically flights with AA are good. The staff are pleasant, welcoming, and efficient.
I liked how when I got on board how fast we ended up taking off but what I truly disliked was how uncomfortable the seats were. There was truly never a time that I could ever get comfortable during both of my flights. The seats could get away during shorter flights but flights 3 hour plus makes it hard to enjoy.
The crew was great and the flight was very smooth. Can’t really judge food since I did not get any because it costs money. The seat was comfortable for what we bought. Thanks!
Crew was great. No entertainment and food and beverage was for purchase only, even water
It was canceled. The flight wasn’t rescheduled, everyone had to figure out their own new arrangements. They said we would get refunded our original fare and receive an additional $150. We received links for $100 only and they expired before we could activate them.
The plane had originated in Las Vegas at 6:30 in the morning and flew to Moline where we boarded. The flight left around 12:30 PM and there were no boxed snacks available and many of the alcoholic beverages were unavailable. I would find it hard to believe that that many of the passengers coming from Las Vegas at 6:30 in the morning, drank and ate that much of the items. I can only come to the conclusion that someone failed to stock the plane for the round-trip. This is a huge revenue failure for the airline and disappointment for the passengers. The flight crew did not seem happy to be there and did not engage with passengers. Allegiant you can do better.
They did not let my husband on the plane with our service animal at the last minute. Do NOT fly this airline with a service animal!
Tight! Seats are not designed for those of us who wear extra-large clothes.
The non-stop flight from Grand Rapids was excellent. I neither expected or needed a budget flight and Allegiant made the trip easy and for an affordable price, Arriving at the Mesa Airport (AZA) is a delight compared to the international airport. For our return flight, we were able to arrive 75 minutes before the flight, return the rental car, check our bag and make it to the gate in plenty of time. That would never happen at most airports.
Easiest flights I’ve ever taken. Plane was comfortable without overly crowded seating.
Terrible. Still have not received the refund from them. They sent it to some account that I don't even know. Spoke with costumer service and they are unable to help.
Terrible. The canceled my entire flight when I requested a refund for a trip frontier canceled trip one way.
Boarding was on time and plane departed as scheduled. There are obviously no amenities (food, drink, entertainment) on Frontier, but there also didn't seem to be any issues with luggage space either.
Inbound plane was on time and flight departed on time with no issues while boarding.
I knew going into this that Frontier, being a low cost carrier, would be pretty bare bones and charge for most extras but this was made up for by the fact that the airplane was a reasonably new Airbus, every employee was great and best of all, Everett Washington is an amazing airport - thanks Frontier for flying there!!!
i was unable to check in the flight. refund requested
It was well done. It was my first time flying with them and I was nervous b/c I have heard of many cancelled and/or delray flights. Everything went smoothly.
Just know that everything, and I mean everything is “ala cart”. 60$ just to put something in the overhead bin. I will never fly Frontier again nor do I recommend them to anyone else.
Frontier is the Walmart of airlines. Frontier has removed adjustability and comfort from their seats to make the flight lighter and save gas. This makes it impossible to sleep on their flights. Their customer service is abysmal. Once, I bought a drink on the plane, and they swiped my credit card on the plane to pay for it. Then I got three weeks of daily notices from my bank telling me they tried to charge the wrong card number over and over again. I tried to call them, but they removed the ability to actually talk to someone that can resolve such a problem from their company to cut corners. The only way to talk to someone in person is to go to the check-in counter at the airport (40 minutes drive from my house). Eventually their system gave up on trying to charge the card, after 21 days of repeated tries. They don't pad their prices even a little to handle customer service issues like missed flights. They also have a blanket policy preventing helping you reschedule a missed flight if their system says you "cancelled" your own flight online. This is a major problem because their website is broken on mobile devices, the only web browser you have at the airport when their gate staff tell you that you have to reschedule your own missed flight online because they can't help you. I tried to reschedule my flight on my android device and instead, their website crashed and "cancelled" my missed flight. When I got to the counter, the agent argued with me for 5 minutes insisting that I intentionally cancelled my own flight (implying I had to buy another flight). She missed the point: the problem was that I could not buy another flight because their website is broken. I left to avoid more conflict with the "customer service" agent. I tried to redress my issue with their only other "customer service" chanel available: the contact form on their website. The response I got was more of the same: you cancelled your own flight, according to our website / computer records, therefore we won't help you. I was trying to explain the problem with their broken website that cost me hundreds of dollars by crashing / malfunctioning and resulting in a cancelled flight, but they only had deaf ears for this problem. Worst customer service I have ever experienced. I will never buy another Frontier flight again, because it is a risky, painful move that I will likely regret often.
What I expected, nickeled and dined and a frontier flight attendant loudly complained about her job and lack of communication as she headed to the gate on her cell phone. Not professional.
I’m not gonna fly Frontier Airlines because booking is not an option. No water or food is for high price, not equipped for health emergency incompetent crew for emergency services. Cheap airline shows it is cheaper in all service categories. Boarding is the best of all airlines!
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