I can't give you any ideas re destinations but as for the plane ride...

We did LHR-YYZ with our son when he was 10 weeks old and that's 8hrs. To be honest it's relatively easy when they're travelling so young - my wife just fed him as the plane went up & down and then he slept/enjoyed looking at the new environment for the rest of the flight.

It gets harder as they get older. We did LHR-SIN nonstop when he was 10 months and that was fine as he wasn't really mobile - crawling a bit but no big deal.

Jet lag also wasn't an issue because he spent so much time sleeping anyway at that age.

The problem starts when he wants to be walking around (as with our trip to the US last month).

Best of luck - if you're like us you'll probably see your travel tail of a little but my son has just logged up 50k miles and he's not even 15 months old!!!