Visas
Most visitors need to apply for a visa in advance, and are often easier to obtain than you might expect. See the Afghanistan Foreign Ministry's visa webpage.
By plane
Kabul International Airport (IATA: KBL) in Kabul is the main entry point to the country. In late 2008, the barely functioning old terminal was refurbished and is now being used for domestic flights, while the brand new Japanese-constructed terminal is up and running and fielding international flights.
The national carrier, Ariana Afghan Airlines, is flying with a small fleet of about 14 Airbuses and Boeings (plus Antonovs). They have daily flights from Dubai, and periodic flights from Frankfurt, Islamabad, Delhi, Istanbul, Baku and Tehran. Ariana is particularly bad at keeping to schedules, flights can be cancelled or delayed without notice.
A better option is the independent operator Kam Air, which has twice daily flights from Dubai, twice weekly flights from Delhi and weekly flight from Almaty, Istanbul and Mashad. Some of the flights on the Dubai to Kabul route stop in Herat if you'd prefer to enter the country there. Pamir Airways is a new private airline that offers daily flights between Kabul and Dubai ($330 inbound, $210 outbound), some stopping in Herat. Safi Air also provides flights between Dubai and Kabul. They are the only safety accredited airline in Afghanistan. Safi is the only Afghan airline allowed to fly into Europe and has direct flights to Frankfurt, Germany. The service is good and planes are sound. Staff are professional.
Air Arabia flies 4 times per week from Sharjah - however they have currently suspended operations. Pakistan International Airlines (PIA) flies 4 times per week from Islamabad and 1 time per week from Peshawar to Kabul. Another route in may be via through Tehran or Mashad in Iran. Iran Air \ has periodic flights from Tehran to Kabul. Air India \ operates six flights a week from Delhi to Kabul
