A US-chartered plane bound for Tel Aviv is scheduled to touch down on Sunday in Prestwick airport, near Glasgow, Scotland, a day after a similar flight used the same airport, Britain's Civil Aviation Authority said.
The demonstrations come amid fierce criticism of Britain's apparent cooperation in the transport of missiles to the Jewish state during its bombing campaign in Lebanon.
George Bush, the US president, has apologised for two earlier flights that stopped at Prestwick and had failed to declare they were carrying missiles to Tel Aviv, the British prime minister's official spokesman said.
Prime Minister Blair has denied that Britain has acted inappropriately and dismissed critics who have called for a ban on US military aircraft landing on British airfields.
''What happens at Prestwick Airport is not going to determine whether we get a ceasefire in the Lebanon,'' Blair told Britain's Sky News in an interview.
''If what people are saying is that we should impose an arms embargo on Israel or indeed on the US, I think that would be very curious indeed,'' he told the BBC.
Britain's Civil Aviation Authority said that the flights on Saturday and Sunday were bound for Tel Aviv from Texas and confirmed special exemption permits had been requested and granted for hazardous materials aboard.
''If what people are saying is that we should impose an arms embargo on Israel or indeed on the US, I think that would be very curious indeed''
Tony Blair, British prime minister
The authority is investigating whether Washington applied for similar exemptions to carry hazardous material on two chartered Airbus A310 cargo planes that refuelled at Glasgow's Prestwick airport last weekend.
Officials are checking claims that those planes carried 28 GBU28 laser-guided missiles.
Aamer Anwar, a Glasgow-based human rights lawyer leading Sunday's protest, said several hundred people are expected to gather at the gates of the airport.