Saul P. Steinberg has bought 5.4% of Texas Air.

Steinberg, through Reliance Group, an insurance and financial company of which he is chairman, bought 699,000 shares in the Dallas-based airline holding company from May 20 to July 10 for between $13.625 and $18. A spokesman for the financier said the purchase was for investment purposes. Louis Marckesano, an airline analyst with the Philadelphia brokerage Janney Montgomery Scott, said that “if a shooting match develops” for control of Trans World Airlines--which Texas Air has agreed to acquire--Steinberg “would be in a good position” to reap a profit.