Yes, the money is taken from your account immediately, regardless of whether you are indeed using a credit card or a debit card. Of course, with a credit card you don't have to settle your credit card account until you receive your monthly bill. If you are making the payment abroad, however, it might take 2/3 days for the payment to be processed.
These days, you almost never actually get a plane ticket. The airline company takes your ID card/passport information when you buy your ticket. Then when you show up at the airport to process your airplane 'boarding pass' from the the check in counter, the airline can see what ticket you bought by looking at your ID card/passport number.
If you change your mind about taking the flight, it's usually best to tell the airline in advance. Good airlines might only charge you 5% of the ticket price to cancel the ticket. Bad airlines might charge you 20-50% of the ticket price to cancel the ticket. Changing the time/destination of your flight will have a processing fee too. Every airline company's rules are different.