Etihad Airways has 74 Aircraft.
Breakdown of different planes via the link below.
As City have hired aircraft previously for Porto, they will have no problem doing something similar again, but I doubt it will be free flights this time. That was a great gesture by Sheikh Mansor due to the COVID pandemic.
I hope City offer stay over including hotel for one night, which I would do.(l'd lump it on my credit card)
I really don't fancy doing 24 hours in and out to Istanbul after doing that to Porto and Lyon. I was absolutely fucked coming back and felt shit the next day.