No, but no operator is, whether mobile or otherwise
My experience with telcos of all stripes is that incompetence and apathy is the rule, not the exception, like the one cheerfully announcing it would take months to restore a $100K/month transatlantic T-3 circuit, circa 1999. I don't think any carrier is reliable enough for a multinational not to have redundant connectivity and contingency plans, whether voice or data, fixed or mobile.
The sole possible exception is SITA (now part of Orange Business Services), which was started specifically to address the airline industry in its far-flung geographical footprint.