NEW YORK — Sen. Charles Schumer is urging airlines to allow families with young children to sit together without paying extra.

The New York Democrat is reacting to an Associated Press story last week detailing how families this summer are going to find it harder to sit together without paying fees that can add up to hundreds of dollars over the original ticket price.

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Sen. Charles Schumer, D-N.Y., speaks to reporters following a weekly strategy luncheon, Tuesday, May 8, 2012, on Capitol Hill in Washington. Schumer has asked airlines to let young children sit with their families for no extra charge. (AP Photo/J. Scott Applewhite)

“Children need access to their parents and parents need access to their children,” Schumer said in a statement. “Unnecessary airline fees shouldn’t serve as a literal barrier between mother and child.”

Since last year, American Airlines, Delta Air Lines, Frontier Airlines and United Airlines have increased the percent of seats they set aside for elite frequent fliers or customers willing to pay extra. Fees for the seats — on the aisle, next to windows, or with more legroom —vary, but typically cost $25 extra, each way.

Airlines are searching for more ways to raise revenue to offset rising fuel prices. Airfare alone typically doesn’t cover the cost of operating a flight. In the past five years, airlines have added fees for checked baggage, watching TV, skipping security lines and boarding early. Fees for better seats have existed for a few years but have proliferated in the last 12 months.

Schumer is asking Transportation Secretary Ray LaHood to issue rules preventing airlines from charging parents more to sit next to kids. He is also asking the industry’s trade group, Airlines for America, to persuade carriers to voluntarily waive the fee for families.

“A parent should not have to pay a premium to supervise and protect their child on an airplane,” Schumer wrote in a letter expected to be sent Sunday to Nicholas E. Calio, the trade group’s president.

The airlines say they try to keep parents and young children together. Gate agents will often ask passengers to voluntarily swap seats but airlines say they can’t guarantee adjacent seats unless families book early or pay extra for the preferred seats.

Airlines have resisted past efforts by the government to further regulate them. Their argument: The cost associated with new rules would cripple an industry already struggling with thin profit margins.

Two years ago, Schumer got five big airlines to pledge that they wouldn’t charge passengers to stow carry-on bags in overhead bins. The promise came after Spirit Airlines became the first U.S. carrier to levy such a fee.