National Order DC DC SANTA MONICA CAL Two Two more airlines have announced orders for four- four Douglas DC 4 transports Pennsylvania Central Airlines purchased purchased purchased pur pur- chased 15 DC to inaugurate minute 60 flights between such stich cities as Washington ton and New York Washington and Pitts Pittsburgh Pittsburgh burgh burg and Chica Chicago o and Detroit National Airlines ordered seven Douglas Doug DC The They will fly stop non N New ew York to Miami in four hours and 38 minutes New York to New Orleans in six hours and 18 minutes Miami to New Orleans in three hours United Air Lines already committed to 15 DC and 20 DC ordered 15 more of or the m per hour hour DC These purchases with others previously announced bring the total ordered by US U.S. airlines to four aUdrien all aU driven en by Pratt Whitney engines and Hamilton Standard propellers