While I understand the concern, I am thinking your W will spew at the email as she will feel controlled. In her mind she may spin it that its ok for the kids to go with you to XX but you are not allowing her time with the kids to go to XY, tit for tat. Honestly, a 5 hour plane ride would not kill your children, if anything .. and this is how my devious mind works ... at worst it will make them cranky, and soley your W's problem, I do feel the more real things get for her, the better chance that she comes to her senses and nothing can get more real than good ole travel stress.
Regardless your W should have her time with the kids, vaca where they wish .. these are things out of your control (for the most part) provided she is not going to move out of state nor put the children in harms way, thankfully my W never seemed to lose it THAT bad.
