(AP) — JetBlue and Spirit Airlines said Friday they will appeal a federal judge’s ruling this week that blocked their plan to combine into a single carrier.

The airlines said they filed a notice of appeal with the 1st U.S. Circuit Court of Appeals, following the terms of their agreement.

JetBlue proposed last year to buy Spirit for $3.8 billion in a combination of the nation’s sixth- and seventh-largest carriers. JetBlue, which outbid Frontier Airlines, said it needed to acquire Spirit to compete more effectively against even bigger airlines.

But on Tuesday, a federal judge in Boston ruled that the deal violated antitrust law. The U.S. Justice Department had sued to stop the deal, arguing that consumers would be harmed and forced to pay higher fares if Spirit — the nation’s biggest discount airline — were eliminated.

The airlines announced their appeal in a statement that provided no other details.