Have lived,IRL, delays from not having a replacement aircraft out base to expecting a replacement aircraft. Good for me it wasn't a business trip
it could be interesting to simulte a dispatch reliability for our aircraft. We could make it variable on quantity of spare parts airline want to keep at stock and age of aircraft.
We could also say that dispatch is higher if you have similar sized aircraft available (with spare hours) that could reprotect the flight
Cost of cancelled flight (reprotecting passengers on other flights, hotels) could be easily simulated as a cost as 150% of the ticket price (as an advarage) for short range up to 200% or more for a long range.
For information airlines sized as BA, AF or LH normally have 2 or 3 aircraft in stand-by (more on winter as shedules are reduced).