Classify the following as either airplanes or helicopters:
 - EC-135
 - DC-10
 - Antonov An 225
 - Boeing 787
 - Bell 206
 - MD-500
 - MD-11
 - Airbus A320
 - Airbus H165
 - Cessna 172
Airplanes:
 - McDonnell Douglas DC-10
 - Antonov An-225
 - Boeing 787
 - MD-11
 - Airbus A320
 - Cessna 172
 
 Helicopters:
 - Bell 206
 - Robinson R44
 - MD-500
 - Airbus H165