Which has the bigger carry-on allowance, Frontier or United?

Frontier: 24 × 16 × 10 in (61 × 41 × 25 cm), up to 35 lb (15.9 kg). United: 22 × 14 × 9 in (56 × 36 × 23 cm). Frontier allows the larger bag.

Which is more reliable, Frontier or United?

In 2025 Frontier arrived on time 70.7% of the time (1.8% cancelled) and United 77.7% (0.8% cancelled), according to U.S. DOT data.

Which has more legroom, Frontier or United?

Standard economy legroom is about 28 in on Frontier and about 30 in on United. Both sell extra-legroom seats.

Which cancels fewer flights, Frontier or United?

In 2025 Frontier cancelled 1.8% of its flights and United 0.8%, so United had the edge (U.S. DOT data).

Are Frontier and United partners?

They aren't in the same alliance (Frontier: none; United: Star Alliance), so miles and status generally don't transfer between them.

F9 vs UA · 2026 comparison

Frontier vs United

Q: Do Frontier and United include a carry-on on basic economy?

Frontier: The Basic fare includes only a personal item. Add a carry-on when you book; it costs the most at the gate. United: Basic Economy includes only a personal item on most U.S. and short-haul flights. A full-size carry-on is allowed on transatlantic, transpacific and South America routes, and for MileagePlus Premier members and eligible United cardmembers.

Frontier wins on a bigger carry-on, a bigger personal item and cheaper checked bags; United wins on a carry-on on its cheapest fare, a more generous carry-on weight limit, more legroom, a better on-time record and fewer cancellations. Here's how they compare on bags, fees, comfort, reliability and loyalty.

Verified Oct 17, 2026By Steven MoHow we check Report a correction

Frontier

Wins 3 categories

A bigger carry-on
A bigger personal item
Cheaper checked bags

United

Wins 5 categories

A carry-on on its cheapest fare
A more generous carry-on weight limit
More legroom
A better on-time record
Fewer cancellations

Quick verdict

Frontier wins on a bigger carry-on, a bigger personal item and cheaper checked bags; United wins on a carry-on on its cheapest fare, a more generous carry-on weight limit, more legroom, a better on-time record and fewer cancellations. Check the cheapest fare's bag rules before you compare prices.

Carry-on size: Frontier: 24 × 16 × 10 in · United: 22 × 14 × 9 in
Carry-on on the cheapest fare: Frontier: Costs extra on basic fares · United: Not on some basic fares
First checked bag (regular economy): Frontier: $29–$63 · United: $45
Standard economy legroom: Frontier: About 28 in · United: About 30 in
On-time arrivals (2025): Frontier: 70.7% · United: 77.7%

Side by side

	Frontier	United
Bags
Carry-on size	24 × 16 × 10 in	22 × 14 × 9 in
Carry-on on the cheapest fare	Costs extra on basic fares	Not on some basic fares
Carry-on weight limit	35 lb (15.9 kg)	None published
Personal item	18 × 14 × 8 in	17 × 10 × 9 in
First checked bag (regular economy)	$29–$63	$45
Comfort
Standard economy legroom	About 28 in	About 30 in
Reliability
On-time arrivals (2025)	70.7%	77.7%
Flights cancelled (2025)	1.8%	0.8%
Network
Alliance	None	Star Alliance
Loyalty program	FRONTIER Miles	MileagePlus
Main hubs	DEN	ORD, DEN, IAH, EWR, SFO

Highlighted values are better for travelers. Fees are for U.S. domestic economy flights; on-time data is 2025 U.S. DOT figures for each airline's own flights.

Bags and fees

Frontier allows a carry-on up to 24 × 16 × 10 in (61 × 41 × 25 cm), and United up to 22 × 14 × 9 in (56 × 36 × 23 cm), so Frontier's is roomier.

Frontier charges for it on its cheapest fare, while United's Basic Economy can be personal-item only.

Frontier caps carry-ons at 35 lb (15.9 kg); United publishes no limit.

Personal items: 18 × 14 × 8 in (46 × 36 × 20 cm) on Frontier, and 17 × 10 × 9 in (43 × 25 × 23 cm) on United.

A first checked bag on Frontier costs $29–$63 on all Frontier flights, and a first checked bag on United costs $45 on U.S., Canada, Mexico, Central America and Caribbean flights.

Basic economy

Frontier (Basic): The Basic fare includes only a personal item. Add a carry-on when you book; it costs the most at the gate.

United (Basic Economy): Basic Economy includes only a personal item on most U.S. and short-haul flights. A full-size carry-on is allowed on transatlantic, transpacific and South America routes, and for MileagePlus Premier members and eligible United cardmembers.

Seats and Wi-Fi

Frontier gives about 28 in of legroom in standard economy and United about 30 in, an edge for United. Frontier: About 28–29 in. United: About 30 in in Economy; 34 in or more in Economy Plus.

On-time performance

In 2025, Frontier landed 70.7% of its flights on time and cancelled 1.8%; United landed 77.7% on time and cancelled 0.8%. That makes United the more punctual of the two. The figures come from the U.S. DOT and count each airline's own flights, not regional partners.

Loyalty and where they fly

Frontier is not in an alliance and United is in Star Alliance.

Loyalty programs: FRONTIER Miles (Frontier) and MileagePlus (United).

Frontier's main hubs are Denver (DEN). United's are Chicago (ORD), Denver (DEN), Houston (IAH), Newark (EWR), San Francisco (SFO). The best choice often comes down to which airline flies nonstop from your airport.

Which should you book?

Choose Frontier if you want…

a bigger carry-on
a bigger personal item
cheaper checked bags
nonstops from DEN

Choose United if you want…

a carry-on on its cheapest fare
a more generous carry-on weight limit
more legroom
a better on-time record
fewer cancellations
to earn and use Star Alliance miles and status
nonstops from ORD, DEN, IAH

On a route both fly, the cheaper ticket isn't always the cheaper trip: add the bags you'll actually bring, and check the fare rules before you book.