Re: International schools
If you're looking at international non-affiliated schools OFS and ISS are actually quite good. They are smaller in size, but the faculty there at both schools are top notch. My son finished at ISS last year with an IB and was accepted by King College, LSE and U of East Anglia. He's at UEA right now and has done extremely well and just loves it there.
So, it really depends on what kind of environment your kids want/desire. As far as American School, my impression of it is it's a beautiful campus, way out in Woodlands and it's also very expensive. The attitude of the students/faculty/parents there is something I really don't care for, but that's a personal thing.
As far as going from Cargo to PAX, not yet. However, there are rumblings about having that similar to CX. The cargo side isn't too bad but you will not fly more than about 55 hours/month.