I'm trying to prepare for the Caymen Islands, and have concerns about
what size bags are allowed as carry on luggage. I went to the American
Airlines website, and found the answer to my question, but I'm having
trouble believing it. Specificly, how could they allow "large size
hiking or camping style backpacks" as carry on? The overhead compartment
wouldn't be big enough, would it? On past flights, I remember having no
room for anything in the overhead compartment, because it was full of
other peoples stuff.

If possible, I'll carry on most or all of my scuba gear, but I wouldn't
risk any complications from having no room for the carry on scuba bag. I
remember brief mention of this stuff recently, but I'd really appreciate
knowing if I can depend on the space to store a "large hiking or camping
style backpack." ...See the information below from American Airlines FAQ
on the subject.

.......from American Airlines--->
As you decide what and how much to pack, here are some pointers:
 
Carry-on luggage is limited to one bag plus one of the following
personal items: a purse, briefcase, laptop computer, or small bookbag
style backpack. Large hiking or camping style backbacks count as
carry-on luggage. Other items allowed beyond the restriction include:
coats or wraps, safety seats for ticketed children or lap children,
diaper bags for ticketed children or lap children, books or newspapers,
small bags of food that are consumable and assistive devices such as
wheelchairs, walkers, oxygen, etc.
 
At some airports, carry-ons may be more restricted. All other luggage
must be checked at curbside or at the ticket counter. Passengers
exceeding the carry-on limit will not be allowed through the security
checkpoint.


.....Thanks, Brad