Democrats in the US Senate on Wednesday failed to pass legislation blocking the sale of F-35s to the UAE, paving the way for Washington and the Emirates to sign an official contract formalising the deal.
But president-elect Joe Biden has yet to take a position on the sale.
The long, drawn-out process could present several other obstacles for the UAE in the months and years ahead as the Biden administration examines key details of the $23 billion deal.
Washington and Abu Dhabi must next agree on a letter of offer and acceptance before US defence contractor Lockheed Martin can start the lengthy process of building the 50 F-35s.
Heidi Grant, director of the Pentagon’s Defence Security Co-operation Agency, which co-ordinates foreign arms sales, said last week that it would be possible for the Trump administration and the UAE to sign the letter before Mr Biden takes office on January 20.
That would be an unusually short time for such a major contract.
Bob Menendez, the Democratic senator who introduced the legislation to block the sale, indicated that much of his opposition was because of the pace at which the Trump administration made the offer.
“I am not opposed to these sales if they make sense or pose no threat to US or Israeli security in the short and long term,” Mr Menendez told the Senate before the vote on Wednesday.
“But these sales require careful and deliberate consideration within the interagency process and by this Congress.”
Emma Soubrier, a visiting scholar at the Arab Gulf States Institute in Washington, told The National that there was much discussion about the letter of offer and acceptance already, even though the month-long congressional review period does not officially end until Friday.
“LOAs can take months to actually establish depending on how on the same page people on both sides are already,” Ms Soubrier said.
“My understanding is the Trump administration has already tried to fast-track this deal.”
Others are more sceptical that the Trump administration and the UAE would be able to finalise the letter before Mr Biden took office.
"It seems unlikely that an LOA on the F-35s, for example, could happen by January 20," Jeff Abramson, a senior fellow at the Arms Control Association, told The National.
“That is a negotiation between the Emiratis and the US. How long that takes is variable. We just don’t know.”
But even if Mr Trump is unable to finalise the letter with the UAE before leaving office, Mr Biden’s foreign policy advisers have not ruled out proceeding with some form of the huge deal.
"The Obama-Biden administration made sure that our most advanced fighter plane would be available to Israel, but only to Israel in the Middle East, because we wanted to make sure that Israel was able to preserve its qualitative military advantage, and we have provided for the sale of some number of F-35s during our administration," Tony Blinken, Mr Biden's nominee to serve as secretary of state, said in October.
“And so, reports that the administration has committed to provide these planes to the UAE is something we would look at very, very carefully.”
Ms Soubrier said Mr Blinken’s remarks did not indicate that the Biden administration “would not actually approve” the sale later.
However, the exact details and cost of a major arms sale often differ, in this case between the Trump administration’s $23bn notification to Congress and the weapons delivery.
"When you look at actual data, figures of notifications, those figures are often a lot higher than what eventually gets delivered," Seth Binder, an advocacy officer at the Project on Middle East Democracy, told The National.
“In part, that’s because when they get down to the nuts and bolts of the LOA, they might narrow it back.
“The terms of the agreement might not follow to the tee exactly what the notifications look like.”
The notification presented to Congress includes the $10bn F-35 sale, another $10bn for precision-guided munitions and $3bn for reaper drones.
Israel’s endorsement of the sale could also bolster support for the arms deal in Washington, relieving some tension among sceptical Democrats when Mr Trump leaves office.
The Israeli ambassador to the US, Ron Dermer, while appearing on MSNBC with the UAE Minister of State and envoy to the US Yousef Al Otaiba, said he was “very comfortable” with the F-35 sale.
Although the Emirates have been looking to buy the F-35 fighter jets since the administration of George W Bush, the Trump administration opted to proceed with the sale after the UAE signed the Abraham Accord to normalise relations with Israel.
The American Israel Public Affairs Committee said this week that it would not oppose the sale.
Other pro-Israel groups in Washington have openly endorsed it as long as Israel receives more US support to maintain its qualitative military edge in the region.