then you ATP which allows you to fly for hire on scheduled routes
The difference between theory and practicality....
The FAA doesn't require an ATP to fly scheduled routes. A commercial license with instrument rating is all they require to be a first officer (copilot), even on a 747 (exceptions for long haul flights when an "augmented crew" is required - there has to be at least 3 pilots with two ATP's rated in the aircraft). That's the theory part.
Practically speaking, no major airline (pax or freight) will likely hire anyone without an ATP - it's a way of weeding out the less qualified from the thousands of applications they get for each available pilot job.
Most people get the CFI before the ATP, BTW. Having the CFI opens a lot of doors job-wise, and can be gotten with a lot less hours (and younger age) than the ATP.
Question for BoeingBoy: I'm 17, have my instrumental, and amd working on my commercial. Will it be hard for me to find a cargo job while I go through college to build up hours?
Just as "passenger airline job" covers a wide range - from bush pilots in Alaska to flying those 747's across the Pacific - "cargo job" also covers a wide range. At the top are the FedEx's, UPS's, DHL's, etc - like any big airline, you'll look a lot better in the applicant pool with a few thousand hours of flight time, preferably turbine or turbojet PIC time, ATP, college degree, etc.
On the other end, there are small cargo companies flying light twins or small corporate type aircraft, such as banks flying cancelled checks to their home offices every weeknight. Those jobs require less experience, etc., but also pay rock bottom wages (think qualifying for food stamps type wages).
The big thing will probably be finding a pilot job near where you go to college with a schedule that'll mesh with your school schedule. Just keep beating the bushes. Unfortunately, right now the big passenger airlines have quite a few pilots furloughed so the competition for available jobs is pretty fierce.
Jim