> never have I seen such a strong push towards offshoring
As I've been working in the airline IT industry, I've observed that the reality is more nuanced.
Core booking and ticketing systems are 'outsourced' to solutions from Amadeus and Sabre. This makes sense not only for many strategic reasons (easier to have airline alliances when the airlines are all on the one system), but also because airlines are in the business of flying planes, not building ticketing systems.
Airlines are often full of loads of legacy and old systems which you just can't hire developers for (in the numbers, and costs, desired) - this is where Indian outsourcing firms come into the play and resolve the shortcomings. They're taking all the jobs and work that no one really wants to do anyway.
However airlines, and many other industries (banks come to mind), are realising that their digital offering is just as much, if not more, a core part of their offering and those are skills they need to bring in house and own if they want to be competent. I'm seeing more and more web and app developers be brought in house so airlines can establish these competencies. Digital/Product agencies are 'stepping in' in the meantime to help out (like Virgin America and Work & Co).