If you are a frequent flyer in East Africa, connecting from one flight to another, which is time-consuming and tiresome, plus the eventual cost of travel are likely to be your top concerns, making this travel option unattractive.
For example, a traveller from Uganda or Burundi cannot fly directly to Dar es Salaam, despite the two countries sharing a border with Tanzania. To fly to Dar es Salaam, one is forced to make a connection through Nairobi’s Jomo Kenyatta International Airport (JKIA) or Rwanda’s capital Kigali.