It stuck out slightly in security bin at SLC It’s like 27” tall so about 3” more than the 24” max. most airlines have. But so far no one’s had me measure it, so maybe that’s a Frontier thing.

Saved me $40 on Alaska, since I had one large bag checked already and needed to get bags anyway.

They encourage gate checked bags anyways since they usually run out of overhead bin space.

Plus less work not having to wheel the carry on the rest of the way. And it lets me put the backpack in the overhead =legroom.