One of the organisers said that he and his colleagues had to scale back the vessels they planned for the flotilla due to pressure from security forces.
Egyptian President Abdel Fattah al-Sisi declared support for the plan on 29 September, describing it as a "step towards permanent and comprehensive peace".
Human rights lawyer Negad al-Borae said the pardon given to Alaa by the Egyptian president offers a ray of hope that other political prisoners would come next.
Israel's strikes on Doha, part of a regional multi-front war it has fought since 2023, have pushed Egypt to revive the idea of an Arab military alliance