Emergency services were called to Waddesdon, near Aylesbury at around midday after a helicopter and an aircraft crashed.
The Rev Mary Cruddas, team rector of the Schorne Benefice, which includes St Michael and All Angel's in nearby Waddesdon, said in a statement that both churches would remain open for prayer.
She added: "Everyone is welcome to light a candle and hot drinks will be available at the back of the church.
"Our thoughts and prayers are with everyone involved in this incident."
Both aircraft came from Wycombe Air Park around 20 miles away - which offers flight training for new pilots.
Air crash investigators have been called to the crash site, in a dense woodland, alongside paramedics, firefighters and Thames Valley Police, who said the first priority was "preservation of life".
Emergency services have revealed that the crash has resulted in "a number of casualties".
It involved a helicopter and another aircraft - and happened just after midday.
RAF Halton, which is around 10 miles away, has said no military aircraft were involved.
Police are co-ordinating the response to the crash and warned there will be disruption to surrounding roads for the rest of the day.
The SCAS spokeswoman said: "We received the call at 12.09pm, for a mid-air collision involving a helicopter and an aircraft in Upper Winchendon, near Aylesbury.
"We sent a number of resources to the scene, including a Thames Valley air ambulance, two ambulance crews, two ambulance officers and a rapid response vehicle."
Waddesdon Manor, on the Rothschild family-owned estate near the crash site, described the crash as a "tragedy" and added it "did not happen at the manor nor have there been any casualties at Waddesdon Manor".
