What do you call a male flight attendant?

A steward.

Answer:

The previous answer is wrong. A steward is a position on a ship, not a plane. The correct answer in American English is Flight Attendant (which is used for both men and women).

In British English, Air Host is is the appropriate term for men.

Note:

A steward is also a position on a plane.

"A person who looks after the passengers on a ship, aircraft, or train." -- Oxford

"A flight attendant" -- Dictionary.com

"An employee on a ship, airplane, bus, or train who manages the provisioning of food and attends passengers" -- Merriam-Webster