Fact 1: Aairplane is used for moving people across bodies of water.

Fact 2: Millions of people fly safely in airplanes every year.

Given the two facts above, answer the question "What transports millions of humans over water every year?" with the following options: 
- helicopters
 - gliders
 - electricity
 - engines
 - airplanes
 - space ships
 - Gravity
 - rivers


 

     airplanes    