Here are the carry on regulations, looks like it may have to be checked in, depending on the breakdown size, so then a hard case is a must 'with a lock".
Airline Carry-On Luggage Regulations
In order to keep the passenger compartment uncluttered and safe, the airlines place rules and size limits on the luggage that each traveler can carry on the plane. The primary rule is the size limit stating that bags carried on board must be small enough to store below your seat or in the overhead compartment. Currently the basic rule is that carry on baggage must be no taller than 22 inches, no wider than 14 inches, and no deeper than 9 inches. In many cases, you'll also have to contend with limits on weight. We've gathered the restriction details of some of the more heavily traveled airlines below:
Use our Carry-On Tool to find luggage that fits the baggage regulations of your favorite airline or browse Carry-Ons
Airline No. of Bags Allowed Maximum Allowable Dimensions Max Weight
Air France
carry-on info 1/passenger 22" x 14" x 9" 26.4 lbs.
You may also carry a purse, computer, briefcase, or small tote
Air Tran
carry-on info 1/passenger 55 linear inches (L+W+H) -
You may also carry a purse, computer, briefcase, or small tote
Alaska Air/Horizon
carry-on info 1/passenger 24" x 17" x 10" -
You may also carry a purse, computer, briefcase, or small tote
American Airlines
carry-on info 1/passenger 45 linear inches (L+W+H) 40 lbs.
You may also carry a purse, computer, briefcase, or small tote
America West
carry-on info 1/passenger 51 linear inches (L+W+H) -
You may also carry a purse, computer, briefcase, or small tote
British Airways
carry-on info 1/passenger 22" x 16" x 8" 26 lbs.
You may also carry a purse, computer, briefcase, or small tote
Continental
carry-on info 1/passenger 51 linear inches (L+W+H) 40 lbs.
You may also carry a purse, computer, briefcase, or small tote
Delta Airlines
carry-on info 1/passenger 22" x 14" x 9" 40 lbs.
You may also carry a purse, computer, briefcase, or small tote
Northwest Airlines
carry-on info 1/passenger 22" x 14" x 9" 40 lbs.
You may also carry a purse, computer, briefcase, or small tote
Southwest Airlines
carry-on info 1/passenger 24" x 16" x 10" -
You may also carry a purse, computer, briefcase, or small tote
Spirit Airlines
carry-on info 1/passenger 22" x 13" x 10" 40 lbs.
You may also carry a purse, computer, briefcase, or small tote
United Airlines
carry-on info 1/passenger 22" x 14" x 9" 40 lbs.
You may also carry a purse, computer, briefcase, or small tote
US Airways
carry-on info 1/passenger 24" x 16" x 10" 40 lbs.
You may also carry a purse, computer, briefcase, or small tote
Virgin Atlantic
carry-on info 1/passenger 22" x 14" x 9" 35 lbs