Both destinations are served by Bhuj (BHJ). Since there's no flight route between them, the best way to travel is by road.
Rann Of Kutch
Fly to Bhuj (BHJ), then travel by road to Rann Of Kutch. Taxis, buses, and private cabs are available from the airport.
Kutch
Fly to Rudra Mata (BHJ), then travel by road to Kutch. Local transport options include taxis, auto-rickshaws, and state buses.