Despite a meeting with Prime Minister David Cameron last month to talk up the merits of a deal, the UAE has decided not to proceed with an order for at least 60 Eurofighter Typhoons.
The value of the proposed deal had been estimated at £6bn.
“All parties have invested significant effort in drawing up Typhoon proposals for the UAE and, recognising the risk, scale and complexity of such a transaction, the group had not built this prospect into its planning assumptions,” said BAE Systems.
The British firm builds Eurofighters as part of a consortium with French firm EADS and Italy’s Finmeccanica.
The group lost out on a deal to supply India with Eurofighters last year but is in talks to sell planes to Saudi Arabia, Qatar and Bahrain.
BAE said discussions with Saudi Arabia had made good progress but “a definitive agreement has yet to be reached”.
If the deal is not done this year, the firm has said it expects earnings per share to be between 6p and 7p lower than forecast.