The Best Software to teach app development to 16-18 year olds?

[Lotuspetal_uk]

Hi guys the summer hols are here which means I've been lumbered with the task of researching potential software for mainly a non specialist IT teacher to deliver.

Does anyone know which software would be the better one for a teacher to deliver app development to students aged 16-18 (which cancels App Inventor out due to age group plus the qualification requires something more complex).

This is what I've come up with so far:

• Developer Android.com (But this might be too difficult for the students given that their previous lower school experience did not have any programming in it at all)

• Another teacher has recommended Flash 5.5+ - but the IT network manager at the school has shot this down due to cost (school doesn't want to pay out for Adobe)

• Windows App Studio - unknown territory for me but another suggestion the above teacher suggested mentioning that it's free.

Is anyone a Computer Science educator here who could suggest which one (or another resource out there) which would tick the boxes for cost and translating to all skills abilities, ready for September this year?

Thanks in advance for any help.
LP