Becoming an Airline Pilot
First of all, the "how to" part of becoming a commercial pilot does not require lists of FAA (Federal Aviation Administration) regulations, or descriptions of exactly how many hours must be logged in each certificate rating, this is side information covered after you already choose a path to becoming an airline pilot, else it's actually pretty meaningless information to a reader.
There are two major ways to become a commercial airline pilot, each of them quite distinct from the other. Some people may wish to join the military and their flight program, while others may wish to go to an Aviation university like Embry-Riddle. The cheaper of the two is definitely the military route, but choosing that path means you must first return on the military's investment, in other words serve your country for a few years. On the other hand, while going to an aviation university may cost money (and it is quite a lot), it is far more of a fast track to a commercial license. As with everything, both the military and university routes have their pros and cons.
The military will prepare you to be a pilot unlike any other, but their goal is not to make you an airline pilot. The military's goal is to make you really good at flying your aircraft; if you fly heavy aircraft like the C-5 it will be more like flying commercially, however flying fighters or bombers is very different. The military route also does not guarantee you a commercial job when you leave, however you will have a much better chance if you flew heavy aircraft because commercial companies like to see flight time on comparable aircraft being logged. The military is also, as previously stated, the cheaper route; it will pay for all flight training required, and even pay your salary just for being an officer in the military. Getting into the military flight training program is also much more difficult than joining a university's, this is because the military is really looking for that elite, best of the best pilot.
Aviation universities have their perks too. Many aviation universities practically guarantee students a job in the right seat of an airliner aircraft (this means co-pilot) when they graduate. The biggest issue with aviation universities is the cost, Embry-Riddle basically charges $48,693 for that prized commercial license from start to finish. However, that guaranteed right seat job doesn't usually make a tremendous amount of money, so it's not like the costs can be immediately payed off. An aviation university will allow anybody into their flight track program that gets accepted into the college, meaning right out of high school with decent grades; so it is pretty easy to actually join a university's flight track program.
Other considerations for becoming an airline pilot is physical fitness, eyesight, reaction and coordination, and natural ability. Flying an aircraft is a demanding task, it takes concentration, fast reaction, good coordination, and very much so good vision (the requirement being 20/20). The first few flights will sap tremendous amounts of energy out of a person, this separates the determined from the jokers.
Regardless of which path is chosen, both will train and fully prepare a person to be a great pilot. It all is based on what is right for each individual, from how much money one can spend to how soon they want a job. The details of regulations, flight log time requirements, and check flights will all be explained when a path is chosen, and it is all part of course information that is taught. The big questions lie in: "Do you want to be an airline pilot?" and "Which path do you want to take?"