Starting June 5, American Airlines passengers seated in the extra legroom spots — “Main Cabin Extra” — will be treated to “complimentary beer, wine and spirits,” The Forward Cabin first reported.

Main Cabin Extra upgrades are available starting at $20, depending on the flight. In economy, sparkling wine is available for $9 per glass — meaning that an upgrade could nearly pay for itself with two glasses of wine.

The airline also announced that passengers who booked the extra legroom seats would also have priority access to overhead bin storage space and earlier boarding than regular economy passengers.

But be forewarned: American Airlines flight attendants are on alert for economy passengers who try to sneak into empty Main Cabin Extra seats to take advantage of the perk. The airlines issued an internal memo earlier this year about passengers bumping themselves up to Main Cabin Extra seats after the cabin door is closed. Flight attendants were directed to use their own best judgement in resolving such issues.

“Flight attendants have flexibility when it comes to solving seating issues within the Main Cabin,” a spokesperson for the airline told The Points Guy. “Main Cabin Extra generally has relatively few empty seats after our team completes the boarding process, so we don’t expect any issues.”

The safest bet is to purchase the upgrade when booking.

Also, while the drinks are complimentary, passengers should know flight attendants also have discretion not to serve anyone who is inebriated.

American Airlines has recently announced other perks for select passengers on select flights. Earlier this year, American Airlines also introduced free alcoholic beverages to passengers on shuttle services from D.C., Chicago, and Boston to New York City.