Can I sell flights from low cost airlines on my portal as well as the bigger airlines?

Yes, low cost airlines can be sold alongside the bigger full service ones, although the two do not always behave the same way. Many flight connections now carry both, so your customer sees a low cost fare and a full service fare side by side and simply picks the one they want. Which low cost airlines actually appear depends on the suppliers you are connected to, because each supplier carries its own set of carriers and no single supplier carries every airline in the world.

The main difference to expect is in what comes with the fare. A low cost airline usually sells a bare seat and then charges separately for baggage, seat choice and a meal, so the first price your customer sees looks lower but the final amount can rise once those are added. Some low cost carriers also handle changes and cancellations under their own rules rather than the usual airline rules, and a few of them do not allow a booking to be changed at all once it is issued.

Payment and ticketing can work differently too. With some low cost airlines the booking has to be paid and confirmed at once with no option to hold it, and what comes back to you is the airline's own booking reference rather than a normal ticket number. That is decided by the airline and the supplier rather than by the portal, so it varies from one carrier to the next.

Before you start promoting low cost fares, ask which of these carriers your suppliers cover on the routes you sell most, and check how changes and refunds work for each one.