London Heathrow Airport issued this statement:

Out of respect for the period of mourning following the passing of Her Majesty The Queen, some flights between 13:50–15:40 on Wednesday,  September 14 will be disrupted to ensure silence during the ceremonial procession.

We anticipate further changes to the Heathrow operation on Monday,  September 19, when Her Majesty’s funeral is due to take place. We will communicate more details over the coming days. We apologise for the disruption caused, as we work to limit the impact on the upcoming events.

The airport also details the impact of the Queen’s funeral:

Out of respect for Her Majesty Queen Elizabeth II, Heathrow will be making appropriate alterations to our operation throughout the period of national mourning.

Changes at the airport

On Wednesday 14th September, some flights between 13:50-15:40 will be disrupted to ensure silence over central London as the ceremonial procession moves from Buckingham Palace to Westminster Hall. Passengers affected by this will be contacted by their airline.

Throughout the period of national mourning, further changes can be expected at the airport, including:

• Observing the National Moment of Reflection with a one-minute silence at 8pm on Sunday 18 September.
• Showing Her Majesty the Queen’s funeral on screens at the airport on Monday 19 September.

Further changes to the airport operation will be communicated in full over the coming days.

Travelling to the airport

The procession of Her Majesty the Queen’s coffin to St George’s Chapel in Windsor on Monday 19 September will impact local roads around Heathrow. Passengers travelling to the airport are advised to consider alternative routes, such as the Piccadilly or Elizabeth Lines or Heathrow Express.