Flight travels at 460km/h so 460 km in 60 min and 230 km in 30 min., so now 460km + 230km=690 km = 60min +30 min. = 90 min.

So 7:30 am + 90 min. = 9:00 am,

Now travel time to airport is 35 min, 9:00 am - 35min= 8:25 am

SO MY ANSWER IS 8:25 AM HE SHOULD LEAVE TO REACH AIRPORT IN TIME.