He called them out after the first incident happend: http://blogs.wsj.com/corporate-intelligence/2013/02/26/elon-...
Boeing probably should have licensed Tesla tech after the first incident.
But even if Boeing had achieved the extremely unlikelihood of being able to get Tesla car batteries modified, fitted to their aircraft and approved by the relevant licensing bodies, it wouldn't have made a blind bit of difference to the totally unrelated Honeywell bit of kit suspected of catching fire in the Ethiopian 787
Interestingly enough, Tesla co-founder and CTO JB Staubel created some kind of hybrid propulsion system for aircraft, that I believe was purchased by Boeing. So there are definitely connections (if not continuity of technology) between the companies.
[Edited for clarity]