Delta Air Lines spokesman Anthony Black told the AP Thursday that the carrier "closely monitors competitive conditions and periodically reviews its pricing of fees. After careful consideration, Delta increased its change fees to remain competitive in the marketplace."
American also confirmed the fee rise but noted that its Choice Essential and Choice Plus fares let customers change reservations at no cost. The tickets are priced higher than a base economy fare, however.
(Read More: American Airlines Fare Revamp Includes Options to Waive Fees)
One industry analyst said that while record-high load factors (or percentage of occupied seats) might warrant the increase, it obviously isn't a customer-friendly move.
"As load factors rise, the opportunity cost of allowing changes rises with it, so while there is a valid economic rationale, it still won't be popular," said airline industry analyst Robert W. Mann.
Less-restrictive coach fares with higher prices and refundable tickets typically don't carry a change fee and remain unchanged at all carriers.
The Associated Press contributed to this report.