1.No, if scientific experts in this field believed there was an unacceptable level of risk to safety of passengers,flight crew, residents under flight paths and aircraft then grounding the planes is a no brainer
2.Definitely not, little willie walsh has got enough reserves to provoke strikes,mess terminal 5 up - and we the tax payer are hard up enough already to be subsidising him and iberian airways and the mikey o'learys of this world
3.No, the decision should be made by a body of .appropriate independent scientific experts with Airlines, government, pilots,flight crews,even unions having an input into the decision
4.Probably, big business interests always end up being accomodated
5.After 3 to 6 months of personally monitoring how many planes fall out of the sky or nearly fall out of the sky and for what reason