Bombardier (Bombardier Stock Quote, Charts, News, Analysts, Financials TSX:BBD.B) has been on a spectacular run this year as the market has been taking a fancy to the business jet maker as economies open up to a new, hopefully post-COVID, reality.\u00a0 But was putting all its eggs in the one basket a good idea for the once great Canadian plane and train-maker? Portfolio manager Andrew Pyle weighs in, saying investors choosing to climb aboard BBD at these prices have a lot to ponder. \u201cIt\u2019s a tough one, especially at these levels around the $2 mark where we've seen the stock rally to,\u201d said Pyle of CIBC Wood Gundy, speaking on BNN Bloomberg on Monday. \u201cAt the end of the day, this is really a bet on what do we think is the future or near-term future for corporate jets, and it\u2019s a huge debate,\u201d he says. Bombardier\u2019s share price has shot up plenty starting this past November and now carrying into September. The stock went from a flatline of around $0.50 to now $1.95, representing almost a four-bagger over less than 12 months. For long-time shareholders, those gains are welcome but still not enough, as BBD\u2019s trajectory going back a number of years had the stock rising optimistically to as high as $5.00 before starting the long downhill. Bombardier\u2019s story, of course, is one where through corporate mismanagement and ill-advised government handouts, the company became a money-losing machine, one which racked up billions in debt and ended up having to sell off most of its divisions one by one until all that remained was, as of last year, corporate jets. The narrowed focus may have ended up being helpful for the balance sheet, but Pyle says it makes for an iffy investment prospect, as Bombardier now becomes dependent upon the winds of change in the business world, which has yet to send its troops back on their business trips in anywhere close to the pre-COVID rate. \u201cOn the positive side, given people's reluctance maybe to get on crowded planes for business travel, they will opt for the privacy of the company\u2019s own jet. So that's in the plus column; in the negative column, again, is the fact that we have in a lot of cases revolutionized the way that we do business globally. We don't need to get on a plane and travel to London to have a face-to-face meeting. We just do it quite nicely over Zoom, and that\u2019s going to work against a company like Bombardier,\u201d Pyle said. \u201cSo, I think at these levels, we probably would not be buying and we might even be looking at maybe taking some profit off the table,\u201d he said. \u201cBut I do think this debate is going to be an interesting one to see how it plays out.\u201d Pyle says an added element to the drama might be climate change. As more and more companies try to make good on their ESG bona fides (environment, social and governance), the temptation may be to forego the jet for video conferencing. \u201cCompanies now are getting scored and it would have nothing to do necessarily with COVID. It comes down to what is your impact, what\u2019s your footprint? And now that we know that we can do business without necessarily hopping on a plane, it's going to be tough,\u201d Pyle said. \u201cAgain, that\u2019s why don't really like the stock at these levels.\u201d Last month, Bombardier raised its full 2021 guidance on the strength of what it called a solid first half of the year. BBD delivered its latest quarterly results on August 5, where the company\u2019s second quarter featured business jet revenue of $1.5 billion, representing a 50 per cent year-over-year increase. The company delivered 29 aircraft over the Q2, saying the global use of business jets continues to climb and is almost back to pre-pandemic levels in North America and Europe.\u00a0 The favourable environment was the cause for management to slightly lift its forecast for 2021 to about 120 business jet deliveries compared to between 110 and 120 previously and revenue of over $5.8 billion compared to over $5.6 billion previously. \u201cBombardier\u2019s raised guidance stems from all-around solid execution in the first half of 2021, greater confidence in market momentum, and our ability to accelerate initiatives supporting our recurring savings objective,\u201d said \u00c9ric Martel, President and CEO, in a press release.\u00a0 \u201cOur team\u2019s concerted efforts have already supported stronger full year margins and have allowed us to focus diligently on our priorities of maturing the Global 7500 aircraft program, executing our aftermarket growth strategy and deleveraging our balance sheet,\u201d Martel said. Bombardier\u2019s adjusted EBITDA for the second quarter climbed to $143 million compared to just $31 million a year earlier, while the company reported free cash flow generation of positive $91 million from continuing operations.