LAS VEGAS (AP) — Two budget airlines in the U.S. and Mexico say they will seek government approval to form an alliance and expand their flights across the border. Las Vegas-based Allegiant and Mexico’s Viva Aerobus said Wednesday they will seek antitrust immunity from the U.S. and Mexican governments. The airlines want to work together on setting schedules and routes. Allegiant says it will invest $50 million in Viva Aerobus as part of the deal. The airlines say they expect to begin flights under the alliance in early 2023, if they win approval from the two governments.