Famed host David Letterman was not a happy camper last Wednesday night after John McCain decided to cancel his interview with him.

David Letterman ripped Republican Presidential candidate John McCain to shreds last week after the 'Maverick' told Letterman he couldn't make the 'Late Night with David Letterman' interview because of the economy.

Our friends at TMZ scoop: McCain supposedly called Dave at the last minute to cancel his appearance because he had to "race to the airport" to go watch after our crappy economy.

But here's the kicker: Later on, Dave cut to live footage of Johnny boy getting his makeup done for an interview with Katie Couric -- only a couple blocks away from Dave's studio and far from an airport.

Go here for video of an angry Letterman. It's not a pretty sight.