TWC Aviation in Van Nuys has been acquired by a Houston rival, creating one of the largest private charter fleets operating out of the United States.

TWC, which has offices and a hangar at Van Nuys Airport, was bought by Landmark Aircraft, a Houston charter service owned by Carlyle Group, a Washington D.C. private equity group.

TWC operates a fleet of more than 50 aircraft based at 25 locations, including the large body Gulfstream G550, Bombardier Global Express and Falcon 2000. Landmark has a fleet of 44 planes, and both companies manage jets owned by third parties.

Landmark also operates a network of so-called “fixed-base” facilities selling fuel and offering other services in North America and Europe, as well as maintenance-and-repair facilities in nine states.

TWC will continue operating as a separate brand offering private charter and aircraft management services during the integration process with Landmark. Edward Frank, who had been chief executive of TWC, is remaining with the combined company with the title of general manager, Landmark Aircraft management and charter.

“When coupled with our current aircraft offering, this expansion of our fleet will produce time and cost savings and increase charter options for all of our customers,” said Ben Murray, Landmark’s president of aircraft management & charter, in a prepared statement.

TWC was founded in 1998 by Andrew Lessman, who made his fortune with Henderson, Nev. vitamin maker ProCap Laboratories. In 2008, the firm relocated to a new hangar at Van Nuys Airport from Burbank Bob Hope Airport. In 2012, TWC expanded into the Asian market through a partnership with Sino Jet Management Ltd., in Hong Kong.

Terms of the deal announced April 3 were not disclosed.