I would say that the mid 2022 is likely to be the earliest that wannabies should consider starting their commercial training if there sufficient indication of improvement. Be super careful about paying up front for any training - there will be lots of financially stressed companies out there. Willie Walsh has just been on LBC - BA won't return to 2019 size until 2024 which is probably a reasonable window for any large companies which survive. Bear in mind that when you do pop out the far end of the training system, salaries may be lower than they have been for the past few years - frequently in times of turmoil, pilot unions are asked to sell the next generation down the river to protect their own contracts by allowing companies to offer a diminished package to new joiners. Personally I have been flying for about 15 years and this is the second time I am having to assess options outside the industry in case I am made redundant. If you are smart enough to fly commercially, you are smart enough to succeed in many other professions which are less turbulent.