That's pretty normal sort of business practice. When it comes to the plane owners (which lease out planes) and/or finance companies acting as suppliers of sort in the industry, they quite ordinarily want to diversify their exposure so as to better manage risk.

It would be pretty interesting to see the write-off amounts of each of IT's creditors involved in the leasing/financing of those airplanes which IT had at the end as a proportion of all such creditors' write-offs for the same reporting year(s).