Are there nonstop flights from Dehradun (DED) to Kolkata (CCU)?

Yes. IndiGo fly this route. Flight time is about 2h 3m.

What is the fastest connection from Dehradun (DED) to Kolkata (CCU)?

via Lucknow ≈ 2h 36m, via Gautam Buddha Nagar ≈ 2h 44m, via New Delhi ≈ 2h 48m (estimated flying time, excluding layovers).

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

Dehradun Jolly Grant Airport (DED) to Netaji Subhash Chandra Bose International Airport (CCU)・1,321 km

Nonstop flights available (1 airline). Flight time about 2h 3m. Nonstop return flights also operate.

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

10 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.