The eight had been due to board a Hungarian airline Malev flight via Budapest as part of the "Welcome to Palestine" campaign which hopes to enable hundreds of activists to spend a week visiting Palestinian families.
"Their reservation was cancelled at the request of Israeli authorities who have drawn up a list of undesirable persons," the airport source said, adding that the eight were turned away when they tried to check in for their flight.
Israel was battening down the hatches at Tel Aviv airport on Thursday, awaiting hundreds of pro-Palestinian protesters as Greece blocked the last boat in a scuppered campaign to ship aid to the Gaza Strip.
Organisers of the "Welcome to Palestine" campaign, which some describe as a "flytilla" in reference to a parallel maritime protest flotilla, say the 600 or so activists -- more than half of them French -- were to spend a week visiting Palestinian families and have "totally peaceful intentions".
France on Thursday warned its citizens of possible trouble at Tel Aviv airport if they take part in the so-called "flytilla."