Hopefully they will be able to identify the 'extra' fuel burnt due to:
1. time/apu fuel burn due airfield congestion due lack of runways
2. taxi time in excess of, say 10 minutes, due too many aircraft waiting o take off
3. holding en-route and a destination due lack of runway capacity
4. fuel burn waiting for parking stand availability
5. finance costs requiring extra staff and aircraft etc due inefficiencies due above.
6. increased CO2 emmisions for ground vehicles awaiting late aircraft due above
7. etc, etc