Following constraints may be applicable for airport slot coordination depending on the level of congestion and vary by each airport:

• Runway capacity
  performance and use of runway system, surrounding area (topography), approach and departure routes, air traffic control capabilities
• Parking capacity
  number of available ramp stands, restrictions on aircraft size, longterm parking
• Terminal/passenger flow capacity
  “passenger throughput”, check-in, arrival, transfer and baggage sorting/area infrastructure, security/customs & immigration facilities, Schengen and non-Schengen areas
• Environmental restrictions
  night ban, night curfews, noise restrictions, noise quotas 
• Other operational restrictions
  security dispositions, special handling etc.