- verifying payment details and confirming the transaction,
- checking seat availability,
- adding the fare information to the PNR, and
- issuing the ticket and sending it to the passenger.
In addition to being issued by airlines, tickets can also be issued by travel product resellers such as travel agencies or travel management companies. To be able to sell tickets on behalf of airlines, these entities must receive special accreditation from either IATA (for those outside of the US) or ARC (for US-based distributors).
Most low-cost carriers (LCCs) operate on the ticketless model, combining the booking and ticketing stages so that no ticket is issued. Those distributors that book LCC flights through GDSs either work on the light ticketing model (it resembles the regular ticketing flow but excludes IATA/ARC payment mediators) or ticketless model (a reseller doesn’t issue any receipt but provides contact and payment information to the airline which sends flight details directly to the passenger).