To clarify: "Never expire" is a promise made by a company, TWA, which now is bankrupt and no longer exists. Thus, there is no one that can perform that promise for you (or provide you the underlying transportation which you were hoping to obtain with those miles), except as was agreed in AA's assumption of the FF programs through the bankruptcy. The planes currently in the air are actually being operated by TWA, LLC, a new company.
"Merger" -- this was not a merger, but an asset purchase. AA thus did not legally succeed the the liabilities of TWA, except those which they agreed to accept (typically those which were associated with particular assets, such as plane leases). To the extent that AA agreed to accept any liability for the Aviators' balances, they agreed to do so only on their terms--i.e., that the miles would be folded into AAdvantage and all AAdvantage rules would apply once the miles were in AA accounts.
Djlawman
[This message has been edited by Djlawman (edited 06-14-2001).]