Travelers headed for Palestinian-controlled areas of the West Bank often report being detained and questioned, sometimes for hours, by Israeli border authorities.
Israel also restricts access to the border crossing with the Hamas-controlled Gaza Strip to foreign journalists, diplomats and aid workers. Some 1.6 million Palestinians live there.
Last July, Israel blocked a similar fly-in effort by preventing dozens from boarding Tel Aviv-bound flights in Europe and denying entry to 69.
Some Israelis accused the government of overreacting to the activists' campaign.
"Instead of waiting to present the crackpot activists with flowers, putting them on buses and leading them directly to their destination in Bethlehem, the heads of the defense establishment and security forces have once again lost their minds," columnist Eitan Haber wrote in the Yediot Ahronot newspaper.
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