Which has the bigger carry-on allowance, Allegiant or Southwest?

Allegiant: 22 × 16 × 10 in (56 × 41 × 25 cm). Southwest: 24 × 16 × 10 in (61 × 41 × 25 cm). Southwest allows the larger bag.

Do Allegiant and Southwest include a carry-on on basic economy?

Allegiant: Fares include only a personal item. A carry-on is a paid add-on, cheapest at booking. Southwest: Even the Basic fare includes a carry-on and a personal item. Checked bags cost extra on Basic, Choice and Choice Preferred fares.

Which is more reliable, Allegiant or Southwest?

In 2025 Allegiant arrived on time 74.5% of the time (0.5% cancelled) and Southwest 77.8% (0.8% cancelled), according to U.S. DOT data.

Which cancels fewer flights, Allegiant or Southwest?

In 2025 Allegiant cancelled 0.5% of its flights and Southwest 0.8%, so Allegiant had the edge (U.S. DOT data).

Are Allegiant and Southwest partners?

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

G4 vs WN · 2026 comparison

Allegiant vs Southwest

Allegiant wins on cheaper checked bags and fewer cancellations; Southwest wins on a bigger carry-on, a carry-on on its cheapest fare, a bigger personal item and a better on-time record. Here's how they compare on bags, fees, comfort, reliability and loyalty.

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

Allegiant

Wins 2 categories

Cheaper checked bags
Fewer cancellations

Southwest

Wins 4 categories

A bigger carry-on
A carry-on on its cheapest fare
A bigger personal item
A better on-time record

Quick verdict

Allegiant wins on cheaper checked bags and fewer cancellations; Southwest wins on a bigger carry-on, a carry-on on its cheapest fare, a bigger personal item and a better on-time record. Check the cheapest fare's bag rules before you compare prices.

Carry-on size: Allegiant: 22 × 16 × 10 in · Southwest: 24 × 16 × 10 in
Carry-on on the cheapest fare: Allegiant: Costs extra on basic fares · Southwest: Included on every fare
First checked bag (regular economy): Allegiant: $20–$50 · Southwest: $45
On-time arrivals (2025): Allegiant: 74.5% · Southwest: 77.8%

Side by side

	Allegiant	Southwest
Bags
Carry-on size	22 × 16 × 10 in	24 × 16 × 10 in
Carry-on on the cheapest fare	Costs extra on basic fares	Included on every fare
Carry-on weight limit	None published	None published
Personal item	7 × 15 × 16 in	16.25 × 13.5 × 8 in
First checked bag (regular economy)	$20–$50	$45
Reliability
On-time arrivals (2025)	74.5%	77.8%
Flights cancelled (2025)	0.5%	0.8%
Network
Alliance	None	None
Loyalty program	Allways Rewards	Rapid Rewards
Main hubs	LAS, SFB, PIE, AZA	DEN, LAS, MDW, BWI, DAL

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

Allegiant allows a carry-on up to 22 × 16 × 10 in (56 × 41 × 25 cm), and Southwest up to 24 × 16 × 10 in (61 × 41 × 25 cm), so Southwest's is roomier.

Allegiant charges for it on its cheapest fare, while Southwest includes it on every fare.

Neither publishes a carry-on weight limit.

Personal items: 7 × 15 × 16 in (18 × 38 × 41 cm) on Allegiant, and 16.25 × 13.5 × 8 in (41 × 34 × 20 cm) on Southwest.

A first checked bag on Allegiant costs $20–$50 on all Allegiant flights, and a first checked bag on Southwest costs $45 on flights within the U.S. mainland.

Basic economy

Allegiant (Base fare): Fares include only a personal item. A carry-on is a paid add-on, cheapest at booking.

Southwest (Basic): Even the Basic fare includes a carry-on and a personal item. Checked bags cost extra on Basic, Choice and Choice Preferred fares.

On-time performance

In 2025, Allegiant landed 74.5% of its flights on time and cancelled 0.5%; Southwest landed 77.8% on time and cancelled 0.8%. That makes Southwest 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

Allegiant is not in an alliance and Southwest is not in an alliance.

Loyalty programs: Allways Rewards (Allegiant) and Rapid Rewards (Southwest).

Allegiant's main hubs are Las Vegas (LAS), Orlando Sanford (SFB), St. Petersburg–Clearwater (PIE), Phoenix–Mesa (AZA). Southwest's are Denver (DEN), Las Vegas (LAS), Chicago (MDW), Baltimore (BWI), Dallas (DAL). The best choice often comes down to which airline flies nonstop from your airport.

Which should you book?

Choose Allegiant if you want…

cheaper checked bags
fewer cancellations
nonstops from LAS, SFB, PIE

Choose Southwest if you want…

a bigger carry-on
a carry-on on its cheapest fare
a bigger personal item
a better on-time record
nonstops from DEN, LAS, MDW

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.