Ethiopian Airlines (IATA code ET) is the sole domestic airline operator and one of the most successful and reputable airlines in Africa and is a Star Alliance member, servicing both the USA and Europe with direct flights.
Bole International Airport in Addis Ababa is the main hub for Ethiopian Airlines with flights to most capitals of Africa. An extremely attractive deal for ET passengers on their way to other East Africa safari destinations is to make a week stop-over in Ethiopia at no additional cost to enjoy the famous Ethiopia Historical Circuit before flying to their final destination.
Other international airlines serviced by Bole International Airport include: Lufthansa, Sudan Airways, Kenya Airways, British Airways, KLM, Turkish Airways, Emirates, Gulf Air, Egypt Air and Fly Dubai. A new runway and international terminal, which was said to be the largest in Africa, opened in 2003.
Many hotels will offer free pickup - be sure to book in advance. If not, upon arrival you may call your hotel for the transfer but may wait up to 1 hour depending on the traffic.
CAUTION: Arriving in the country without a major currency such as euros or US dollars is not recommended, especially if one has not obtained a visa prior to arrival. Travellers cheques and cash can be exchanged at the airport. There are several ATMs in the international airport terminal (Terminal 2) accepting VISA-branded cards (both debit and credit cards), but they're not reliable. You should have some cash in any major currency (USD, Euro, Pounds, Swiss Franc, Japanese Yen)
One way to get in from Sudan is via the border village of Metema.
One way to get in from Kenya is via the border town of Moyale. The road from Kenya to Ethiopia through the town of Moyale is much better and well maintained. On the Kenyan side of Moyale the road is horrible and is known for banditry so be careful and make sure you have plenty of time, at least 24 hours, to travel from Moyale to Nairobi.
Though not advisable for foreigners, bush taxis oftentimes ferry people between Hargeisa and Jijiga, though it will be necessary to change busses at the border between Somaliland and Ethiopia.
Public transportation brings you to the border. To/from Sudan or Kenya you just walk to the other side. If you arrive at the border towns late at night, try not to cross the border in the dark. Wait in the town and do your travelling in the morning.
Buses that cover some distance start in early morning. This implies that if you arrive during the day you would be stuck at least until the next morning.
From Djibouti you can take a small bus to the border (2-3h) where you will find buses to Dire Dawa. This road is a dirt track and the trip takes at least half a day, at nightfall the bus stops and you resume travel the next day. From Ethiopia into Djibouti, a bus leaves supposedly around midnight (buy tickets during the day at the office in the centre of Dire Dawa). This arrives at the Djibouti border in the morning where you change onto a different bus to get to Djibouti City. It is a good idea to take a tuk-tuk (auto-rickshaw) to the bus station as hyenas wander the streets of Dire Dawa at night.
From Khartoum, Sudan. There is an easy and comfortable route possible entirely by pubic bus. Take a microbus (5SDG) from any of the Khartoum bus stations to Mina Bahri (N15.527495, E32.543703). Pay 3SDG entry to the terminal, walk inside the terminal building and ask for Al Gadaref at one of the ticket windows. Once you have your ticket (100SDG) confirm the bay number and departure time. The ticket seller will then direct you to a government office where you must provide a photocopy of your passport photo and visa pages and pay 20SDG to have your ticket stamped with permission to travel. The standard permit to travel is not required on this route. Alternatively, accept the services of one of the many touts in the terminal who will organise your ticket, arrange your passport copies and travel permission, and take you to the correct bus. The journey takes around 5 hours and the bus is a comfortable AC coach.
Once at Al Gadaref bus station take a microbus to the souk (2SDG) and stay overnight at one of the hotels in the city centre (100SDG for two bed private room, shared bucket showers). Leave early the next morning and take a microbus or walk to the Gallabad direction bus station, which is different to the one you arrived at (N14.024227, E35.395183). Take a bus to the border town of Gallabad (36SDG). The border crossing process involves visiting the police office to register your arrival at Gallabad, then the Sudanese immigration office to register your departure, then the Sudanese customs office. You then walk across the border and visit the Ethiopian immigration office and the Ethiopian customs office.
You will be approached by touts offering to change money and direct you to the various offices. This is not necessary since each office will direct you to the next, and there are banks for changing money on the Ethiopian side. Once in Ethiopia, buses for various destinations depart from a bus station around 3km up the road (not 7km as you will be informed). A rickshaw costs 10ETB or walk. From the bus station take a bus to Gondar (100ETB) or Metema.