Are there nonstop flights from Ottawa (YOW) to Houston (IAH)?

No. The fastest connection is via Toronto, about 3h 51m of total flying time.

What is the fastest connection from Ottawa (YOW) to Houston (IAH)?

via Toronto ≈ 3h 51m, via Chicago ≈ 3h 59m, via Washington ≈ 4h 6m (estimated flying time, excluding layovers).

from 15,000 ANA miles (economy, one way, based on the published award charts).

Ottawa Macdonald-Cartier International Airport (YOW) to George Bush Intercontinental Airport (IAH)・2,418 km

No nonstop flights. The fastest connection is via Toronto (YYZ), about 3h 51m of flying time (layover not included).

With milesANA 15,000 miles+ (via YYZ)Economy, one way, estimate. Tap a connection for miles by cabin.

None.

17 one-stop options, sorted by estimated flying time. Tap one to see the airlines on each leg and booking links.

Times are estimated from distance. Check schedules, frequency and availability with the airline or a booking site.