(iStock ) United has long had its Economy Plus option, offering "up to 5 extra inches of legroom" in coach, starting at $9 per flight for shorter hops.
Tips for getting cheap upgrades, more legroom when you fly
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AUGUST 30, 2012
George Hobica, FoxNews.com

JetBlue, Delta, United and other airlines will sell you a few extra inches of legroom at the front of the economy cabin or at exit rows for a reasonable upgrade fee.
Read more: Fox News