Slot mobility occurs on a limited scale at Schiphol. Annually, 2 to 3 per cent of all allocated slots are exchanged between airlines. Slots are mainly exchanged between airlines belonging to the same airline group. In addition, slots are exchanged for joint operations. Mergers and acquisitions only sporadically lead to slot exchanges. The impact of slot mobility on competition is currently limited, as slots are mainly exchanged between airlines within the same airline group or alliance.

Facilitating slot trading could increase slot mobility and thus have a positive impact on market access, competition and efficient allocation of scarce airport capacity. Ensuring sufficient slot mobility becomes more important as scarcity at Schiphol increases. Slot trading is most effective when trading takes place in a public marketplace and slots are sold on a permanent basis:

• Public marketplace versus bilateral trading: A public marketplace increases transparency and enhances the effectiveness of slot trading. In a bilateral system, slots are less likely to be traded to direct competitors (including new entrants). Sellers prefer a bilateral system because they benefit from reduced price transparency and because it allows them to control which competitors obtain their slots. Buyers, however, benefit from as much transparency as possible and therefore prefer a public marketplace;
• Permanent sale versus temporary lease: Slot leasing allows airlines to temporarily transfer redundant slots to other airlines. Slot trading in the UK and the US mainly consists of leases, where slots are leased for a certain period of time to airlines that are not direct competitors. An important disadvantage of slot leasing is that the slots do not return to the slot pool. Airlines requiring slots therefore become dependent on competitors to lease slots. Due to the temporary nature of slot leases and the fact that leases generally do not occur between direct competitors, slot leasing has a limited impact on competition.

However, slot trading may also result in less market access, as fewer slots might return to the slot pool (to which new entrants have priority) and slots are potentially harder to finance for (smaller) new entrants.

Uncertainty about Schiphol’s future capacity makes it difficult for airlines to determine the value of a slot and may be a barrier to trading slots. Consequently, support for facilitating slot trading is currently limited among airlines.