The mourners initially gathered at the Ethiopian Airlines-owned Skylight Hotel near Bole International Airport.
Some held up framed photographs of young loved ones.
The room filled over the course of a half hour, becoming a packed, makeshift grieving centre.
Couples held each other, slumped forward in their chairs, their gazes downcast. Some men held their heads in their hands. Women in head scarves leaned for comfort against the chests of their relatives.
All 149 passengers and eight crew aboard the flight were killed when their Ethiopian Airlines Boeing 737 MAX 8 crashed six minutes after taking off from the high-altitude capital of Ethiopia.
Nine Ethiopians were killed in the crash, along with 32 Kenyans, 18 Canadians, and eight people each from China and Italy.
A total of 35 nationalities were on board.
Family members of people who died on the crashed have however hit out at the airline for what they term as lack of adequate information.
Angry family members left the meeting at the hotel, saying that they are frustrated by a lack of answers to their questions.
An Ethiopian Airlines staff member, also wearing black, told the mourners the airline would offer free accommodation as well as counselling services.
The embassies of Canada, China, and Kenya had also asked Ethiopian Airlines to designate conference rooms for their citizens affected by the disaster.
Early on Thursday morning, those rooms, decked in the national flags of those countries, lay empty.
The airline said on Twitter that an Ethiopian delegation had flown the black boxes from flight ET 302 to Paris for investigation.
An Ethiopian delegation led by Accident Investigation Bureau(AIB) has flown the Flight Data Recorder (FDR) and Cockpit Voice Recorder (CVR) to Paris, France for investigation.
— Ethiopian Airlines (@flyethiopian) March 14, 2019
The contents of the flight data recorder and cockpit voice recorder will provide critical details about what happened, experts say.