Five major U.S. airlines have promised Sen. Chuck Schumer (D-N.Y.) that they will not charge passengers for their carry-on luggage.

American Airlines, Delta Airlines, JetBlue, United Airlines and U.S. Airways have all responded to the senator's request favorably over the past week, he told CNN on Sunday.

They each promised during individual conversations with the top Democrat not to follow the lead of Spirit Airlines, which announced two weeks ago it was considering a new $45 fee on passengers who store luggage overhead, according to reports.

"In the last week we have gained tremendous momentum in our effort to keep carry-on bags free," Schumer said. "We have begun to put the brakes on runaway and out-of-control airline fees.

"I am pleased some of the major carriers have responded to our efforts and have agreed not to charge for something that has always been free," added the senator, who is leading the charge to introduce legislation that would outlaw the practice.

However, it is unclear whether the airlines' recent assurances will deter a congressional effort to begin taxing those companies for "non-essential" services.

Current law taxes airlines only for tickets they sell, not baggage fees and other charges they impose on their customers. Sens. Schumer, Bob Menendez (D-N.J.) and others have recently explored an end to that loophole, though it is unclear whether lawmakers will still approve it as part of a bill to reauthorize funding for the Federal Aviation Administration.