Aviation experts say Boeing should be dreaming up its next clean-sheet jet — even if it's a decade away

1. Boeing needs to finish current aircraft projects before launching new models. 2. Development of a new narrowbody depends on acquiring an efficient engine. 3. A new plane is likely a decade away, facing certification hurdles. 4. Boeing's stock has risen nearly 23% this year amid production ramp-up. 5. CEO Kelly Ortberg is improving Boeing's operational quality and investor confidence.