Discount airlines are often much more strict about their fares. For example, while in "fat" airlines they usually allow some baggage over the weight limit, WizzAir will charge you €6 for each kg over the limit. Also, some airlines have lower limits than the usual 20 kg. A few kilograms of weight can double your ticket price. Check your terms carefully and weigh your luggage before a journey.

Most discount airlines try to lower airport fees, so they often use smaller airports, sometimes quite far away from the city they state they fly to. For example Paris Beauvais Airport is some 90 km from Paris, bus costs about €13 one-way and it takes about 1h15 to get to Paris (TAXI would be €130-150 one-way).

Following competition from discount airlines, main carriers such as BA have also cut their fares on competing routes, and are often only about 20% more expensive than discount airlines, a price worth paying if the journey to the airport is cheaper and faster. Sometimes they can even be cheaper than discount airlines, especially during public holidays.

Many discount airliners are "point-to-point" airlines, and do not sell connecting tickets if you need to take two planes to reach your destination. This means you might need to collect your luggage and check it in again for the next leg of the journey. Another risk is that several low cost carriers do not take responsibility if you miss your connection, even if your connecting flight is with the same airline. This could force you to purchase a new ticket for the next flight. Some low cost carriers will help you out though, so check their rules.