( CNN ) -- Attention passengers : United Airlines is cracking down on travelers with oversized carry-on luggage . The airline says it is motivated not by money -- the airline charges $ 25 for checked luggage -- but by complaints that some passengers are hogging space in the overhead bins . To address those gripes , United recently e-mailed frequent fliers reminding them of the size restrictions for carry-ons . And employees were told to keep an eye out for large carry-on bags . `` This is solely about ensuring the greatest number of customers with standard-sized carry-ons are able to store them onboard , '' a spokesman said . The airline stressed it is not changing its policy but is trying to more strictly enforce it . If your bag does n't fit in the bag measure at the security line , be prepared to be directed back to the ticket counter to check the bag for a $ 25 bag fee . Passengers who get through the security checkpoint with an oversized bag will not be sent back to the ticket counter , a spokesman said . Instead , the bag will be gate-checked for free . Even if your large carry-on could technically be squeezed into the bin , United said it takes away space from other customers if it 's not within the size restrictions ( 9 x 14 x 22 inches , including handles and wheels . ) The airline retrofitted 152 airbus planes with larger bins . They say their newer planes acquired in the past 10 years also have larger bins . Oversized carry-ons is a frequent problem on domestic flights and less so on international flights , since most international fliers headed to a destination for a longer period usually check luggage . How to avoid baggage fees : Wear your luggage . A tale of lost luggage and faith in government restored . TSA loosens rules on international alcohol . What do you think ? Are you a bin hog ? How should airlines manage bin space ?
United Airlines says it will more strictly enforce its carry-on policy . The airline has been criticized for the new rules that require passengers to check their bags and limit how many items they can bring onto a plane. The policy has n't changed but more oversized bags may end up checked for $ 25 .