"It won’t fit." The three words you don’t want to hear when trying to go board. To avoid delays and possible checked bag fees, follow are the size requirements:
The Carry On Luggage may not exceed 45 linear inches (or 114 cm) in combined length, width and height, including any handles and wheels, with the exception of small musical instruments that fit in the overhead compartment space or under-seat space available at the time of boarding
Luggage must meet carry on size limits (approximately 22" x 14" x 9" or 56 x 35 x 23 cm). Reference size check templates located at ticket counters and gates.
Passengers traveling on Delta Connection flights, and only those flights with fifty (50) seats or less, are only permitted to carry personal items on board the aircraft due to limited overhead space. Personal items must be able to fit securely under the seat in front of the passenger. All carry-on luggage bags within Delta's size restrictions will be gate checked, free of charge, during the boarding process and returned upon deplaning. Please ensure that a pink Gate Claim/Planeside tag is securely attached to the carry-on item. Assistive devices are not subject to this restriction.