Not applicable. The very fact that SS age changes is due to empirical changes in longevity across generations (and the financial impact on SS). So it's not a 14th amendment issue. Believe me, it would have been tried in court if it was.

Military benefits are irrelevant, just because a certain employment package was offered in the past, doesn't mean it can never be changed and must be available in perpetuity to all comers. That's ridiculous. Flip side of that is annual raises for inflation... better just lock all the pay tables where they were on Jan 1st 1900. Status Quo!

Also as an aside, service members do not have any sort of airtight employment "contract"... retirement provisions are set by federal law, and could be completely changed or revoked at any time by congress (no constitutional entitlement to mil or any other pension). Obviously politically unpalatable, but that's the only protection you have.

Bottom line you can't enact an age limit (which is already an exception under federal law) and then apply it inconsistently because union intra-mural politics.

Personally I think it should have a gradual phase-in, to minimize disruption for employers and employees, but even that might be illegal. The ADEA does not allow businesses to discriminate for their "convenience" or to "avoid disruption"... they'd have to come up with a better reason. Maybe just maybe if ICAO did a phase-in they could justify matching that.