After growing fears from villagers that loved ones' graves would be demolished to pave the west London hub's expansion, the question was put to the airport to confirm what the proposals covered.
A Heathrow Airport source told getwestlondon: "Any changes to the Harmondsworth cemetery are not part of the proposals and will remain as it is."
It is not the first dispute over uncertainty around demolition plans, after British Airways chief executive Willie Walsh said he not given any formal warning of the proposals , which go straight through the BA offices.
He said: "We were never actually informed or advised by Heathrow that they intended to knock down our headquarters." This claim was strongly denied by the airport.
A "ramp" for planes to take off could be built over the M25 as part of the third runway plan, transport secretary Chris Grayling said in October shortly after the government made its announcment.
Mr Grayling said it would be a "cheaper and quicker" option rather than building a tunnel for the M25 underneath the new runway.
He indicated the decision would mean the least amount of disruption for drivers.
Mr Grayling said: "It is a cheaper and quicker way of doing it."
Keep up to date with the latest news in west London via the free getwestlondon app.
You can even set it to receive push notifications for all the breaking news in your area.