Boeing Co. and some of its airline clients got an instant boost from Wednesday’s up grounding of 737 Max jets across Europe, but the move also portends more-strict safety reviews of future US aircraft by the region’s aviation regulator.The long-awaited decision formally allowing the reopening of commercial 737 MAX operations in Europe followed pledges from the head of the European Union Aviation Safety Agency to maintain better independence from the Us in certifying Boeing’s long range 777X and other new aircraft models.As part of that tougher positioning, Patrick Ky, EASA’s executive director, emphasized that allowing 737 MAX flights was based on the agency’s assessment “carried out in complete independence of Boeing or the Federal Aviation Administration.” Mr. Ky had previously endorsed the hardware, software and pilot-training files affecting MAX fleet, which were devised and tested with European collaboration. But on Wednesday and the days heading towards the reveal, Mr. Ky repeatedly emphasized the EASA performed its own tests and analyses-and would continue to follow the same pattern for other aircraft types in the future.