Delta Airlines, United Airlines and Southwest Airlines all have luggage separated into two categories. Checked luggage is luggage which has to be left at the flight check-in desk and will be put in the plane's storage hold. Carry-on luggage is usually one smaller bag that can be brought with the passenger onto the plane.
For carry-on luggage, Southwest Airlines limits the dimensions to 10"x16"x24", while Delta says bags must be no bigger than 22"x14"x9" and United says the bag's length, width and height should not surpass a total of 45 inches. All three airlines are in agreement that the dimensions of checked bags can vary but must not exceed a weight of 50 pounds.
While most sharp objects such as box cutters and knives have been banned from carry-on luggage, scissors that are less than four inches, and screwdrivers and other tools less than seven inches long are still permitted. Several different kinds of weapons including hand guns are allowed in checked bags, though they do need to be unloaded and disassembled in order to be acceptable.
