His official John McCain 2008 - John McCain for President site has this information:

"Doug McCain has been a pilot with American Airlines since 1990. He currently flies as a First Officer on the Boeing 777 out of JFK International Airport. Prior to American Airlines, he flew the A6-E Intruder in The United States Navy. "

I can't comment about his views about unions or airline management, however. I guess past voting record is really all we have to go on.