What the NMB told swamt is true, they DO NOT have jurisdiction over union alliances or mergers.
What is occurring here is that neither the IAM nor the TWU will file for representation on their own with the NMB. They will file, AS ONE, with the NMB as the IAM/TWU alliance. The memberships at AA and US never having a say on alliance before the vote.
So 700s example would play out as the IAM/TWU alliance is certified, and the individual certifications of the TWU at AA and the IAM at US are extinguished.
Minus any intervenors once an STS investigation is concluded the vote is either the alliance or non-union. The IAM/TWU has denied the membership a say in this alliance, and are counting on them not to vote "no union"
As swamt has said, the memberships at both AA & US need to educate themselves. Specifically with the ability to have another group, chosen by the membership, file as an intervenor.
Again from one of my previous posts ...
Until there is a completed merger, there can't be an investigation into a Single Transportation System or STS.
Until there is a completed NMB STS investigation there cannot be an election.
If/When the NMB STS investigation is complete, AND the merged carriers are considered a STS for the class and craft in question, then there is a window for intervenors to file a showing of interest and be added to the ballot.
If you are satisfied with the IAM/TWU alliance, then simply wait and vote accordingly.
If you are NOT satisfied, then take action and have your choice for representation file as an intervenor when the time comes.
The choice is still yours to make.