United Express announced plans Tuesday to double the number of flights offered between LA/Palmdale Regional Airport and San Francisco International Airport.

The regional air carrier operated by Chicago-based UAL Corp. will offer four daily roundtrip flights between the airports starting Sept. 3. United Express started in June of last year offering two daily flights from Palmdale, becoming the first commercial airline to operate at the airport in several years.

Officials said they hope the additional flights will spur growth at the airport and help it become a viable regional alternative to increasingly crowded Los Angeles International Airport.