They had come to pay their respects to Yared Getecho, the 29-year-old captain of Ethiopian Airlines Flight 302.
He was in control of an ultra-modern Boeing 737 MAX 8 passenger jet when it crashed six minutes into its journey from Addis Ababa to Nairobi.
Members of the congregation were dressed in black and we heard sobs and occasional wails from the mourners.
Captain Getecho was described as quiet but friendly; an accomplished pilot who loved what he was doing.
After an hour or so, the pilot's father, Dr Getachew Tessema, arrived and sat quietly at the front of the hall.
A small number of people rose to give speeches, praising their friend and colleague.
"Today's [flight] roster is a one-way street to paradise, a new roster of everlasting life, never to be rescheduled again," said one mourner.
Later, Sky News spoke to Dr Tessema about his son, who was described as a passionate flyer and a high achiever.
"[He was] ahead of his time, not even 30 years old and they promoted him to captain," Dr Tessema said.
"[He] was very eager, respected his job, he used to like it and went to America, to Boeing a couple of times.
"He did very well... now he met with this, unexpected. Well, sometimes you can't change your destiny."
Dr Tessema called on Ethiopian Airlines to create a memorial for all who died at the crash site and he spoke about the difficulty of recovering his son's remains.
"[It was a] terrible accident, [those on board were] all crushed, there are no bones, no skulls I was told, everyone is sawdust, so I have nothing to send to his mom," Dr Tessema said.
"I was hoping to get something and take it to where he came from but there is nothing. He is in soil now in Ethiopia."
Before the ceremony began, I spoke to a number of pilots about the Boeing 737 MAX series and it was clear that cockpit crews in Ethiopia are seriously concerned about the plane.
Five months ago, an identical airliner operated by Lion Air crashed off the coast of Indonesia.
Two pilots told me the plane was harder to control than older versions of the 737 and they said there was widespread dissatisfaction with the training and information provided by Boeing when pilots move to the MAX series.
"Boeing sold this plane to airlines by telling them they didn't need to retrain the pilots to use [the MAX]. They said it was exactly the same but it isn't true," said one.
The 737 MAX series is fitted with a new software system called the manoeuvring characteristics augmentation system (MCAS). It automatically lowers the nose of the aircraft if the flight computer judges the aircraft to be in danger of stalling.
Unable to manually override the software, the Lion Air pilots struggled to gain altitude before their 737 MAX 8 crashed into the sea with the loss of 189 people on board.
The Ethiopian pilots told me they were not made aware of the MCAS when the new aircraft was put in service, adding that Boeing "provided two bulletins with information points (about the computer software) after the Lion Air crash".
This they argued, was simply not enough.
In a report in the Wall Street Journal on Tuesday, a senior Boeing official was quoted saying the company decided against providing more details to cockpit crews for fear of inundating them with too much technical information.