LONDON — BBA Aviation said on Wednesday that it had agreed to acquire Landmark Aviation, a provider of refueling and other ground services at airports, for $2.1 billion in cash from the Carlyle Group, the private equity giant.

The deal is expected to significantly expand BBA’s Signature Flight Support business, a so-called fixed-base operator that provides refueling and other aviation support services to the owners and operators of private, business, military and commercial aircraft.

After the transaction, Signature would offer support services at 189 locations, including 133 sites in North America.

“This is a transformational step in the continued execution of BBA Aviation’s strategy that is both strategically and financially compelling,” Simon Pryce, the BBA chief executive, said in a news release. The deal would deepen the company’s exposure to the business and general aviation market, he added.