GRAHAM Dwyer brought his wife and children to a "Family Day" event at his model aeroplane flying club three days before Elaine O'Hara (right) went missing, the jury heard.
Mr Dwyer was seen with his family on a brief clip from the DVD made of the event in Roundwood on August 19, 2012.
John Flynn told Sean Guerin SC, prosecuting, that he was secretary at Roundwood Model Aeronautical Club in 2012, when the accused was a member.
There were around 35 people in the club and events were run in conjunction with the Model Aeronautics Council of Ireland (MACI).
Mr Flynn said he knew Mr Dwyer reasonably well as a member and would have seen him "maybe a dozen times" over the course of a year.
Events included ones in which other clubs came along and took part, as well as family days which were run for their own members to come and take part.
A "scale" competition took place on June 11, 2011, which involved scaled down versions of full-sized models. He said the accused took part in this and came fifth.
DVDs were then played back to the jury, two of which were from the club's family day on August 19, 2012.
The first showed Mr Dwyer flying a "Wot 4" multi-purpose model plane and the second showed the accused talking with a woman and two children.
"That was Mr Dwyer and I believe his family," Mr Flynn said.
Further DVD footage was shown from June 24, 2012, when the accused was seen flying a blue, black and white "Extra 300" plane.
Club diaries were then presented in evidence.
Mr Flynn said it was up to members to sign in in the diary. He confirmed that there were no events held at the Roundwood site on August 22, 2012.
Patrick Kenny, who was involved in Shankill Radio Flying Club said the defendant was also a member of that model aeroplane club.
The trial continues.