Former Air Force technician Tony Hui still recalls vividly the 1972 National Day Parade, when he was part of the team that sent 21 aircraft in the air, back to back.

"We were all gathered around one television screen, counting the planes as they went up one by one," said Mr Hui, now 66.

The technically challenging manoeuvre was what Mr Hui, part of the first batch of NSFs to be enlisted into the Air Force in 1970, signed on for. He retired as a first warrant officer in 2004.

"We worked day and night for months. Everyone, from the maintenance crew to the pilots, had to play his part. It was very satisfying when all the planes went up," he added.

The camaraderie built up from the early days of the Air Force is still going strong, as a group of more than 300 former Air Force servicemen who worked at Tengah Airbase holds meet-ups every month.

The last major event in April was attended by about 200 people.

About 20 NSFs were posted to the Air Force as the first batch, recalled Mr Andrew Chua, 66, who was one of them.

"Our posting read 'technical squadron'. Nobody knew what it was, not even our instructors at the School of Basic Military Training," he said.

Like Mr Hui, Mr Chua became a regular in 1971. He said the family-like bond and mutual respect within the squadron made him want to continue his service.

"Even junior NSF technicians like us were respected by the pilots because we understood that everyone's contribution was important for an aircraft to fly," said Mr Chua.

The pioneers agreed that NS still remains relevant in its 50th year. Mr Chua said: "So many things have improved, like training standards and safety, but NS is still about the defence of our country."

Mr Hui said: "NS must be a part of every citizen's life because it is our responsibility to our nation. If we don't defend our homeland, who will?"