(from a talk by an anonymous IBM employee)
DOS Airlines - Everybody pushes the airplane until it glides, then jumps on and lets the plane coast until it hits the ground again, then push again, jump on again and so on and so on.
MAC Airlines - All the stewards, stewardesses, captains, baggage handlers and ticket agents look the same, act the same and talk the same. Every time you ask questions about details, you are told you don't need to know, don't want to know, and everything will be done without you even having to know so just shut up.
OS/2 Airlines - To board the plane, you have your ticket stamped 10 different times by standing in 10 different lines. Then you fill out a form showing where you want to sit and whether if should look and feel like an ocean liner, a passenger train or a bus. If you succeed in getting on board the plane and the plane succeeds in getting off the ground, you have a wonderful trip ...except times when the rudder and flaps get frozen in position, in which case you have time to say your prayers and get yourself prepared for the crash.
WINDOWS Airlines - The terminal is nice and colorful, with friendly stewards and stewardesses, easy access to the plane and an uneventful takeoff. Then the plane blows up without any warning whatsoever.
WINDOWS NT Airlines - Everyone marches out on the runway, says the password in unison and forms the outline of a plane. Then they all sit down and make a whooshing noise like a plane.
Windows95 Airlines - The captain has been announcing boarding plans for about a year and as soon as it's ready you'll be told where you are going. In the meantime you can stand at the window and crane your neck with reporters from every magazine on the continent.
UNIX Airlines - Everyone brings one piece of the airplane with them when they come to the airport. They all go out on the runway and put the plane together piece by piece, arguing constantly about what kind of plane they are building.