Combining a trip to Nepal and Bhutan offers a fantastic opportunity to experience the unique cultures and stunning Himalayan landscapes of both countries. Here's a breakdown of how you can approach this:Key Considerations:
Flights:

The most common way to travel between Nepal and Bhutan is by air. Drukair and Bhutan Airlines operate flights between Kathmandu (Nepal) and Paro (Bhutan).
Planning your flights in advance is crucial, as these routes can be in high demand.

Visas and Permits:

Both Nepal and Bhutan have specific visa requirements.
For Bhutan, most foreign nationals (excluding Indian nationals) must arrange their visas through a licensed Bhutanese tour operator.
Nepal offers visas on arrival for many nationalities, but it's always best to check the latest requirements.

Tour Operators:

Many tour operators specialize in combined Nepal and Bhutan itineraries. They can handle all the logistics, including flights, visas, permits, and accommodations.
Using a reputable tour operator can simplify the planning process and ensure a smooth trip.

Timing:

The best time to visit both Nepal and Bhutan is during the spring (March to May) and autumn (September to November) seasons. These periods offer pleasant weather and clear skies.1

General Itinerary Outline:
Arrival in Kathmandu, Nepal:

Begin your journey in Kathmandu, exploring its rich cultural heritage and historical sites.
Visit iconic landmarks such as Swayambhunath Stupa, Boudhanath Stupa, and Pashupatinath Temple.

Flight to Paro, Bhutan:

Take a scenic flight from Kathmandu to Paro.
Explore Paro's stunning landscapes and cultural treasures, including the iconic Tiger's Nest Monastery.

Thimphu and Beyond:

Travel to Thimphu, Bhutan's capital, and immerse yourself in its unique blend of tradition and modernity.
Consider visiting Punakha, known for its beautiful dzong (fortress).

Departure:

Depart from Paro or return to Kathmandu for your onward journey.

Tips for Planning:
Flexibility: Be prepared for potential changes in flight schedules or weather conditions.
Altitude: Both Nepal and Bhutan are at high altitudes. Allow time for acclimatization to prevent altitude sickness.
Cultural Sensitivity: Respect the local customs and traditions of both countries.
Travel Insurance: Ensure you have comprehensive travel insurance that covers medical emergencies and trip cancellations.
By carefully planning your itinerary and working with reputable tour operators, you can create an unforgettable experience exploring the wonders of Nepal and Bhutan.