What size bag can fit under an airplane seat?

Related questions

1. How many bags can you bring on a plane?
2. Can you bring a backpack and a carry on a plane?
3. Where do I put my prescriptions when flying?
4. Does a backpack count as a personal item?
5. Where do you pack medication when flying?
6. Do airlines weigh hand luggage?
7. How do I change my Aegean flight?
8. What do airlines consider a personal item?
9. Can a backpack be checked luggage?
10. Is a handbag considered a carry on?

Tags

1. #approximately
2. #below
3. #carry
4. #space
5. #inches
6. #wheels
7. #items
8. #maximum
9. #measurements
10. #exact
11. #including
12. #airline
13. #handles
14. #width
15. #seats
16. #release
17. #luggage