"Our aircraft flight line has melted in the heat, so all flying at Cranwell has been stopped," the source told Sky News on Monday.
Cranwell's officials have been "dragging tar around" on their boots, as well as on the wheels of training aircraft, since the start of summer, the source said.
An air force spokesperson, on the other hand, denied that flights had been halted, saying only that the main service area of the base was "currently unavailable for routine use," as quoted in the report.
"Flying training is not affected and will continue by using alternative service areas," the spokesperson said.
The temperature in the United Kingdom has risen sharply in recent days, reaching 32 degrees Celsius (89.6 Fahrenheit). Meanwhile, the UK national weather service, Met Office, warned that temperatures would keep rising.
The source added that the training of about 60 students on elementary flight has been affected.