Not to go too off topic, but let’s nip this one in the bud.

IAG owns BA. BA cannot be liberated or stripped out from IAG, in the same way that your house or car can’t be liberated or stripped out from under you, unless you choose to let them go.

I cannot see any strategic rationale from IAG’s perspective to separate BA from the rest of the group (ie by IPO’ing BA as a separate company, either to new investors or on a demerger basis). Realistically, the only world in which IAG agrees to let BA go is if they get a silly money offer from a purchaser. Potential buyers could only really be another airline group (which just won’t happen in the current climate) or private equity - in which case, be very careful what you wish for...