Most airlines allow passengers to bring on both a carry-on and a personal item like a backpack, laptop bag, purse, briefcase, shopping bag, etc. The general rule of thumb is that your personal item is smaller in dimension than your carry-on bag and it can fit underneath the seat in front of you.
Where should I keep my backpack on a plane?
The cabin luggage is allowed only if the airline has enough space in the overhead bin or under the seat. If there is no space in the plane, the airline authorities can ask you to remove your bag and place it along with other check-in luggage.
Can I put my backpack in the overhead bin?
Is a small backpack a personal item or a carry-on?
In most cases, backpacks are considered personal items as long as they fit under the seat in front of you. For example, if you use a backpack as a personal item and put it under the seat in front of you, you can then use a duffel as a carry-on bag as long as it's under the airline's size requirements.
Will my bag fit in the overhead compartment?
Though you might find an inch or two of a difference with various airlines, the standard domestic carry-on luggage size is 22" x 14" x 9", which includes the handle and the wheels. This size limit ensures your bag — and ideally everyone else's — will be able to be stored safely in the overhead bin for your flight.