In a written statement issued this morning, Grayling said that work to analyse more than 70,000 responses to a consultation on the draft Airports National Policy Statement (NPS) - launched in February - "is progressing well".
The NPS, when formally adopted, will form the policy basis for assessing future applications for airport expansion in the South East.
But in this morning’s statement, Grayling signalled that the timetable for desingating the NPS has been extended.
He said: "The timing of the election, in particular the need to re-start a Select Committee inquiry into the draft Airports NPS means we now expect to lay any final NPS in Parliament in the first half of 2018, for a vote in the House of Commons."
When launching the consultation on the draft NPS in February, Grayling had said that the government expected to lay a final Airports NPS before Parliament "for debate and an expected vote in the House of Commons by winter 2017-18".
A statement of principles agreed between Heathrow Airport Limited and the secretary of state for transport committed the government to designate an NPS on airport capacity which supports the development of the scheme "by no later than 31 July 2017".
The airport is targeting a construction start date of 2022 and intends that the new runway capacity is operational and in use by the public by 2026.
The application for Heathrow’s new runway will be determined under the Planning Act 2008 regime for nationally significant infrastructure projects.
In a report published in February, the Environmental Audit Committee said that the government must provide greater detail and assurances on key issues including air quality, carbon emissions and noise impacts ahead of the publication of the final NPS document.