"Indeed,.. and that ment building structures much larger than bicycles - not to mention that fuselages were 'welded' not brazed, indicating even higher thermal output was required than brazing bicycles."

Aircraft are larger, but the welding is done on fairly light tubes of small section for the most part. A main triangle tube is a pretty large one, and a BB is huge. Also, you don't need to heat anything more than the puddle which is a dot at the end of the torch. There are large scale needs is large clusters, but that can get to be a multi torch job.