The Government of the United States. US ambassadors have their own budget for their travel expenses.
Their sponsors!
Eklil Ahmad Hakimi is the Ambassador to the US for Afghanistan.
Mohamed Tawfik is the Ambassador to the US for Egypt.
Tatoul Markarian is the Ambassador to the US for Armenia.
Josko Paro is the Ambassador to the US for Croatia.
Peter Taksoe-Jensen is the Ambassador to the US for Denmark.
Hans Peter Manz is the Ambassador to the US for Austria.
Hersey Kyota is the Ambassador to the US for Palau.
Nestor Mendez is the Ambassador to the US for Belize.
Jan Jozef Matthysen is the Ambassador to the US for Belgium.
Cyrille Segbe Oguin is the Ambassador to the US for Benin.
Mahamat Nasser Hassane is the Ambassador to the US for Chad.