Originally Posted by
F-16GUY
That makes sense for a single aircraft. But I think that when multiple aircraft from the same company are involved, something just doesn't add up.
The flight plan will include a few different parts to the fuel plan. The taxi fuel, the trip fuel, the alternate fuel and the final reserve fuel. In addition to those there is the contingency fuel. Most airlines use statistical contingency fuel (might be called something else) and it gives the crew an idea of how much extra fuel is routinely used on a route from A>B (an average of hundreds of flights to keep it simple). On a thursday in March, this will probably be a low figure, on a saturday in August, it will be a high figure. It should give the crew a decent starting point for thier fuel decision and encourages them not to take less as obviously the airline want the flight to reach the destination.
Crew will take extra fuel if the weather looks bad (today it didn't) or there are ATC delays (such as strikes, equipment failures etc), or they'd prefer an extra comfort margin for whatever reason. Maybe the captain is new and wants a better margin for another 5 mins of thinking time, but they don't just fill the tanks. The two aircraft that ended up diverting came from performance limited airfields (short runway, lots of hills etc - Look up Innsbruck for pretty pictures) so they can't just put on an endless supply of fuel. They do have other options, but business sense would dictacte that rather than offload passengers on a day with decent weather, on a quiet day of the week at a quiet time of year.
Don't forget that easyjet are BY FAR the largest operator into this airfield and therefore any issues (a sudden closure of the runway) will far more likely hurt them than another operator.