What are the average carry-on measurements?

While each airline sets its own carry-on luggage size limits, as of 2015 the maximum size for most is 45 linear inches, states the Federal Aviation Administration. Passengers with luggage that exceeds 45 linear inches should expect to have them checked before boarding the aircraft. It is important to check with the specific airline for its most updated carry-on limits.

The Federal Aviation Administration recommends that passengers "think small" when choosing a carry-on bag and to plan on checking more and carrying less onto the plane.

One example limit set by three United States Airlines, American, Delta and United/U.S. Airways, is 22 inches x 9 inches x 14 inches for domestic flights, as of 2015. International flights typically use 21 inches as their limit rather than 22, states Consumer Reports.