Which airlines allow a 24 × 16 × 10 in carry-on?

It fits the carry-on limit on 3 of 28 airlines: Southwest, Frontier and Sun Country. It’s too big for American (2 in too tall), Delta (5 in over the total), United (2 in too wide), JetBlue (2 in too tall), Alaska (5 in over the total), Allegiant (2 in too tall), Hawaiian (5 in over the total), Breeze (2 in too tall), Avelo (2 in too tall), Ryanair (2.3 in too tall), easyJet (2 in too tall), British Airways (2 in too tall), Wizz Air (2.3 in too tall), Jet2 (2 in too tall), AirAsia (2 in too tall), Malaysia Airlines (4.7 in over the total), Batik Air (4.7 in over the total), Singapore Airlines (4.7 in over the total), Scoot (4.7 in over the total), Cathay Pacific (2 in too tall), Air Canada (2.3 in too tall), WestJet (2 in too tall), Jetstar (2 in too tall), Qantas (2 in too tall) and Virgin Australia (2 in too tall).

No: it’s bigger than every published under-seat limit, the largest being 48 × 34 × 23 cm on Qantas. It has to go in the overhead bin.

Free in every fare on Southwest. On Frontier and Sun Country it’s a paid cabin bag: only a smaller under-seat bag is free. On Delta, Alaska, Hawaiian, Batik Air, Cathay Pacific and Jetstar it’s over the carry-on limit and no under-seat size is published, so it’s free only if it fits under the seat in front of you. On American, United, JetBlue, Allegiant, Breeze, Avelo, Ryanair, easyJet, British Airways, Wizz Air, Jet2, AirAsia, Malaysia Airlines, Singapore Airlines, Scoot, Air Canada, WestJet, Qantas and Virgin Australia it’s too big for the cabin and would have to be checked.