The Nuclear Decommissioning Authority (NDA) has said radioactive material could potentially be flown to and from Scotland and the US.
Last month, the UK and US governments agreed that material could be exchanged, with the UK receiving a type of uranium used to diagnose cancer.
The NDA is funding improvement work to enhance the runway at Wick John O’Groats Airport.
The airport is about 30 miles (48km) from the Dounreay nuclear site.
Under the UK-US deal, it has been proposed that highly enriched uranium (HEU) stored at Dounreay be sent to the US.
The NDA said flying the material was among options being considered, but also said no decisions have been taken.
A spokeswoman for the NDA said: “The protection of the public and personnel is of paramount importance at all times. For those reason we are unable to disclose information about the transport arrangement that’s could jeopardise the security of this material.
“It has been proposed that a quantity of HEU may be exchanged with the US in return for material to be used in the production of medical isotopes for Europe.
“The upgrades to the airport in Wick will be done to ensure that this is one possible option to allow the transport to take place.”