RTBF named the two as Khalid and Ibrahim El Bakraoui, saying Khalid last week rented an apartment in Brussels under a false name where police found Abdeslam's fingerprints after a raid.
Police arrested Abdeslam, Europe's most wanted man, in a dramatic operation in Brussels on Friday that had been hailed as a "victory" in Belgium's campaign against terrorism.
Khalid is also linked to renting an apartment in the southern Belgian city of Charleroi from where Abdeslam and the other Brussels-based Islamic State jihadists set off to carry out the November 13 Paris attacks which left 130 people dead.
Other reports Wednesday said one of the brothers, who they did not name, could have been involved in the separate attack Tuesday on the Brussels metro station of Maalbeek, which left about 20 dead.
More From This Section
Belgian police earlier Wednesday issued an appeal for information about the two men believed to have blown themselves up at the airport.
The police posted several tweets with the caption "Terrorism: who knows this man?", showing CCTV close-ups of two men pushing trolleys with suitcases through the airport departure hall.
A third man, dressed in a light coloured jacket and wearing a dark hat, who was shown with the two others in a CCTV grab issued Tuesday, is believed to have fled the scene and is now the subject of a massive manhunt.