An Illinois man is suing Southwest Airlines over the carrier’s August 2010 decision to stop honoring vouchers for free alcoholic beverages that were given to “Business Select” travelers, according to court documents.

The suit was filed by Adam Levitt against the discount airline, which had for years given fliers who purchased premium Business Select seats coupons for alcoholic drinks, which normally cost $5 each.

Previously, the drink coupons had no expiration date. Southwest’s new policy, however, allows Business Select passengers to use their vouchers only on the day of travel.

The lawsuit, which is seeking class-action status, claims that the policy change is tantamount to a breach of contract.