America will lead the world into the jet age.

带领世界步入喷气式飞机时代。

As the jet age nears its centenary, even the historic pace of improvement is becoming tougher to sustain.

随着喷气机时代接近一百周年，即使是历史性的进步步伐也变得越来越难以维持。

The last frontier in air travel was more than half a century ago when we went from propeller aircraft into the jet age, and it's been a long time since we had a step forward.

航空旅行的最后一个前沿领域是在半个多世纪以前，那时我们从螺旋桨飞机进入到喷气式飞机时代，而我们已经很久没有向前迈出一步了。