I understand that liquidity is a concern in the short-term, however companies which invest in times of a crisis will come back stronger afterwards. I understand that they cannot run the full refurbishment program now, however when we see demand coming back gradually, they should use the incoming cash-flow from operations for investments in the still grounded part of the fleet.
One of the advantage when planes are stuck on the ground is that retrofitting erase the costs of opportunity as they cannot fly