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

Discover: 55 × 40 × 23 cm (21.7 × 15.7 × 9.1 in), up to 8 kg (17.6 lb). United: 22 × 14 × 9 in (56 × 36 × 23 cm). Discover allows the larger bag.

Are Discover and United partners?

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

4Y vs UA · 2026 comparison

Discover vs United

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

Discover: Economy Light includes the carry-on and personal item but no checked bag. 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.

Discover wins on a bigger carry-on and a carry-on on its cheapest fare; United wins on a more generous carry-on weight limit and a bigger personal item. Here's how they compare on bags, fees, comfort, reliability and loyalty.

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

Discover

Wins 2 categories

A bigger carry-on
A carry-on on its cheapest fare

United

Wins 2 categories

A more generous carry-on weight limit
A bigger personal item

Quick verdict

Discover wins on a bigger carry-on and a carry-on on its cheapest fare; United wins on a more generous carry-on weight limit and a bigger personal item. Check the cheapest fare's bag rules before you compare prices.

Carry-on size: Discover: 55 × 40 × 23 cm · United: 22 × 14 × 9 in
Carry-on on the cheapest fare: Discover: Included on every fare · United: Not on some basic fares

Side by side

	Discover	United
Bags
Carry-on size	55 × 40 × 23 cm	22 × 14 × 9 in
Carry-on on the cheapest fare	Included on every fare	Not on some basic fares
Carry-on weight limit	8 kg (17.6 lb)	None published
Personal item	40 × 30 × 15 cm	17 × 10 × 9 in
Network
Alliance	None	Star Alliance
Loyalty program	Miles & More	MileagePlus
Main hubs	FRA, MUC	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

Discover allows a carry-on up to 55 × 40 × 23 cm (21.7 × 15.7 × 9.1 in), and United up to 22 × 14 × 9 in (56 × 36 × 23 cm), so Discover's is roomier.

Discover includes it on every fare, while United's Basic Economy can be personal-item only.

Discover caps carry-ons at 8 kg (17.6 lb); United publishes no limit.

Personal items: 40 × 30 × 15 cm (15.7 × 11.8 × 5.9 in) on Discover, and 17 × 10 × 9 in (43 × 25 × 23 cm) on United.

Basic economy

Discover (Economy Light): Economy Light includes the carry-on and personal item but no checked bag.

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.

Loyalty and where they fly

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

Loyalty programs: Miles & More (Discover) and MileagePlus (United).

Discover's main hubs are Frankfurt (FRA), Munich (MUC). 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 Discover if you want…

a bigger carry-on
a carry-on on its cheapest fare
nonstops from FRA, MUC

Choose United if you want…

a more generous carry-on weight limit
a bigger personal item
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.