There are Vietnam flights into several airports in the country. However, if you fly to Vietnam from the United States, South America, or Europe, you will most likely land in Ho Chi Minh City or Hanoi. These are the two primary international airports in the country, and the only direct flight to Vietnam from outside of Asia will land at one of them. Points of origin from outside Asia are only from Russia; Frankfurt, Germany; the United Arab Emirates; and San Francisco. Even these flights will stop somewhere (generally in Asia) on the way. This is not necessarily a bad thing, as several Asian airlines are widely accepted as among the best in the world.
There is also an international airport in the city of Da Nang, which is located in the center of the country. An international flight to Vietnam landing in Da Nang will only originate in another Asian country. If Da Nang is your final destination in Vietnam, you will have to fly there from Hanoi or Ho Chi Minh City unless you are coming from a country in Asia. Even though the nearby UNESCO World Heritage Site of Hue has its own airport facility, Da Nang is used for this destination by many, and they get to Hue using the coast highway. Other cities with Vietnam flights include Can Tho near the southern tip of the country, Dalat with its historic golf courses; Hai Phong for immediate access to Halong Bay; and Nha Trang; the center for diving in the country.
Once you fly to Vietnam you will find you can get fairly cheap intra-country Vietnam flights to various parts of the country, even to the lovely Phu Quoc Island, which has an excellent airport facility quite close to the most popular beaches and most of the island's hotels. For the best cheap airfare to Vietnam you might consider vacation packages. These will often include your international flights as well as several other features such as meals, accommodations in hotels, most meals, and some tours. Sometimes, the cost of the entire package will be less expensive than buying a flight to Vietnam by itself. This is especially true of cruises, as some cruise lines have very attractive bulk rate contracts with the airlines.
Many people who fly to Vietnam depart the country using a different form of transportation. This is true of cycling tours in the Mekong Delta that often include neighboring Cambodia and Thailand. It is also true of the longer river cruises on the mighty Mekong River, which also often include Cambodia nd Thailand. Additionally, all three of these countries are popular as add-on extensions to vacation packages elsewhere in Asia. Pre- or post-trip extensions generally last for three to five days. This doesn’t give you a great deal of time to explore the country, so an extension will generally concentrate on only one area—usually Ho Chi Minh City or Hanoi, Bangkok or Phuket Island, or the incredible ruins of Angkor Wat in Cambodia. More rarely, an extension might be a short cruise in beautiful Halong Bay.