Carry Bag

How big can the second carry-on bag be?

I am going on a plane trip next month and the carry-on says that it can not be more the 45inches total in demension, but no where can I find how big your second carry-on (purse, briefcase...........) can be. How big is the room under the seat? Would I be able to use a backpack as my other bag???

The second bag is usually defined on the airline's Web site - you'll have to look for it a bit closer as it is not in the usual ticket information. And it depends on the size of the aircraft itself. The smaller airplanes will not allow a carryon luggage (one with wheels and a handle) and a big backpack - they will make you check one of them. But some of the larger airplanes would probably let you. There are times when I have actually taken a carry-on luggage, backpack and purse - but the flight was not full and there was plenty of room in the overhead compartment.

Suggestion: If you do want to take a carry-on piece of luggage and a backpack, make sure all of the items you really "need" for the flight are in one of them - just in case they make you check one at the last minute if the flight is full (usually they would request the rolled luggage be checked).