Voyager Jet Center, a full charter service carrier, is making a $15 million investment in the Allegheny County Airport in West Mifflin.

The company, which has grown from three to 43 employees in the five years it has operated at the airport, plans to build two hangars, a fixed-base operating center for its clients and parking areas for airplanes and cars.

Mike Dolan, vice president in charge of expansion, development and government affairs, said the Allegheny County Airport Authority gave his company the right to develop five acres at the western end of the airport.

He said the land is part of what was known as the 5-23 Runway. When that runway was converted to a taxiway in 2003, he said, it created a "development opportunity."

Until then, he said, "There hasn't been a whole lot of space around the airport" that was available for development.

JoAnn Jenny, spokeswoman for the airport, said this Voyager Jet project was the first significant development at the county airport in at least 25 years.

She said the airport authority was moving forward with another project that is unrelated to the Voyager Jet expansion.

The authority announced this month that it planned to demolish 15 small aircraft hangars to make way for 12 new hangars that are to be built next year.

Ms. Jenny said funding of this $2 million project would be provided by the airport authority and federal grants.

She said all month-to-month leases would be terminated and that tenants in the hangars that will be torn down will have to vacate the airport by April 30.

She said tenants would be offered an opportunity to rent in the new hangars, but that rental fees would be higher. Some tenants are upset by these changes, which were spelled out at a tenant meeting last week.

"There is a vocal minority who are opposed to these changes," Ms. Jenny said, but she emphasized that the changes were needed to keep the airport competitive.

The Voyager Jet expansion has begun.

Mr. Dolan said details hadn't been finalized for the fixed-base operating center, which will have a pilots lounge, a lobby, a weather center for pilots and a staging area for passengers.

But, he said, the paving of the ramp and the parking lot for the facility has begun.

Mr. Dolan said Voyager Jet provides airplane management and is a full-service provider of fuel, catering and ground transportation for its clients. The company provides executive charter services 24 hours a day to corporate and private users.

Mr. Dolan said the company hoped its expansion would create opportunities and jobs at the airport, which is the fifth busiest in Pennsylvania.

He said the airport's proximity to Downtown Pittsburgh, about eight miles away, made it attractive to new development.

"We like to call it the private aviation hub of Western Pennsylvania," said Dan Stainer, director of marketing for Voyager Jet.