Let's clarify some things for you guys before things get completely misunderstood.
Air One is the cargo brokerage firm and has been around quite a while. It is part of a wider group with presence in/links to Dubai, Moldova and Romania. This is the company that secures the cargo business.
One Air is the UK airline that some of the above work gets "subbed" to. In the UK, the two offices are next door to each other. In terms of ownership of the company, that's on public record which you can Google.
In terms of roster stability. It often gets messy with a lot of cancellations (hence delayed training) because the older 747s suffer from a fair amount of unreliability. They are converted cargo aircraft and literally the first generation of 747-400s coming up to 35 years old, so no surprises. One Air, being the only 747 operator in the country, has to source a lot of parts from Europe and beyond. One Brexit benefit is that spare parts fitted to UK registered aircraft often need paperwork signing off by the UK CAA even though they were previously signed off by an EASA state. Repairs might take a few days but the paper work can often take weeks. The impact to the company is quite big through no fault of their own.
The 777s are delayed by almost a year. Now due for June (and for once Boeing look like they might just achieve that date). Once they are online, the operation will be a lot more stable. The plan for the 777s to operate the shuttles mainly to Hong Kong and back whilst the 747s will do more ad-hoc style work.
Anyone joining One Air as non-TR must be prepared for a year in the training system. Which in a year from now might be down to 9 months but who really knows? It will be slow because we don't fly that much right now. If flying once a month is not for you or you get impatient sitting around, I'd advise you to look elsewhere (roster has a lot of RES periods). Many pilots who joined as non-TR are released as Cruise pilots after a couple of sectors but are still waiting for line training to be released as fully fledged handling pilots (Captains and FOs/SOs). For TR pilots, I think 4? sectors to online. As mentioned, very friendly atmosphere with a proper employment contract and benefits (HR department is internal). Most people are directly employed.
There are some contract pilots from FCI who were hired to bridge the gap but their contracts are up for expiry after 2 years. There's a chance to go permanent.