PHILADELPHIA (CBS) – Airlines are taking measures to deal with growing passengers and shrinking seats.

The CDC says the average American has gained about 15 pounds in the past two decades.

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Meanwhile, airlines have cut about six square inches of seat space, to economize.

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According to USA Today, airlines have turned to offering vouchers to customers who complain of discomfort from crowding seatmates.

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Some airlines require large travelers to buy two seats.