Machines at the airport

Why do we have machines at an airport? --

Can a machine spot dangerous things? --

How can machines help to move bags? --

How can machines help to move people? --

What are the biggest machines at an airport? --

What other machines help airplanes? --

Which machines help airplanes in the ice and snow? --

What stops airplanes from crashing into each other? --

What does this machine do?.