Gilgit Airport (IATA: GIL) operates flights from Islamabad on Pakistan International Airlines. The 40-minute flight through the mountain corridors — the plane threads between peaks that dwarf it — is spectacular, but operates only in good visibility. Flights are cancelled regularly, often without advance notice, and passengers can be stranded for days waiting for a weather window. Never book a flight out of Gilgit with a tight connection in Islamabad.
The alternative is the Karakoram Highway from Islamabad: a 20-hour bus journey through some of the most dramatic road scenery in Asia. NATCO (Northern Areas Transport Corporation) buses and private coaches run daily. The trip is tiring but gives you a ground-level sense of the mountains and the villages that the flight completely misses. Most travellers find the journey worthwhile at least one way.