Shares of Southwest Airlines Co. (LUV) - Get Report fell 1.3% on Tuesday after the airline announced Monday that it expects a key revenue measure to fall by 3% in the second quarter because of reduced advertising following the death of a passenger on a flight in April.

Other airlines were also falling in tandem with Southwest on Tuesday. Delta Airlines Inc. (DAL) - Get Report was down 1.1%, American Airlines Group Inc. (AAL) - Get Report was down 1.65%, and Alaska Air Group Inc. (ALK) - Get Report fell 0.82%.

A woman died after the engine on a Southwest plane exploded and shrapnel flew through the plane's window and struck her. The fatality was the first on a U.S. airline in nine years, according to the National Transportation Safety Board. 

Still, U.S. air travel remains some of the safest in the world. rated four U.S. airlines -- Alaska Air, Hawaiian Airlines, Delta and United Continental Holdings Inc.  (UAL) - Get Report -- among the top 20 safest airlines in the world.

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The rate of plane crashes and fatal accidents has declined for the past three years even as the number of flights and passengers have hit record highs. U.S. airlines carried nearly 7 billion passengers on 80 million flights since the last fatality on an airline in 2009. 

Despite the unprecedented safety run, higher gas prices that could lead to higher ticket prices along with the bad press from recent airline incidents has scared Wall Street. 

The NYSE Arca Airline Index was down 1.1% on Tuesday.