National Geographic : 1952 Dec
"BIRDS OF A FEATHER'. American Airlines again led all other do mestic lines in 1951 with a total volume of over 2.5 billion passenger miles! Ameri can's passenger load also increased, as did its daily use of aircraft; all reliable indica tions of profitable operations. Significantly, too, American continues to be one of the country's lowest cost operators. Sinclair lubricants helped American ac complish this remarkable performance record. American's aircraft maintenance standards are of the highest in the busi ness; and year after year, in fact for 18 years without interruption, American has used Sinclair aircraft engine oil exclusively! Constantly, more and more "leaders" look to Sinclair. Complete comprehension of every phase of lubrication produces the superior Sinclair oils and greases that prove worthy of this trust . . . and gives added proof that Sinclair is a leader in the highly competitive petroleum industry. JL!Il [ ( SINCLAIR OIL CORPORATION * 600 FIFTH AVENUE * NEW YORK 20, N.Y. Mention the National Geographic-It identifies you wif NC f~ik ".