Boeing’s latest postponement of its much-delayed 787 jetliner is disappointing customers, further eroding its reputation and costing a lot of money.

But the jet maker is not alone.

Airbus has confronted a host of problems with its mammoth A380 that caused the aircraft to reach production two years late, and perhaps out of step with the market.

The problems at both companies illustrate the difficulty of stretching to build unprecedented 21st century aircraft using 21st century technology. These are the first plane makers to take on the composite-material and global supply chain challenges. And the solutions they develop, if successful, will help keep the two jet makers in the lead against new competitors in China and elsewhere.