Boeing is enjoying an impressive winning streak.
The company's shares just logged their sixth consecutive quarter of gains, and have risen in 11 of the last 13 months. The stock is on pace to close out this quarter as the Dow's best performer, wrapping up its best quarter since 2009. And the aircraft manufacturer has seen a 94 percent rally in the past year.
Even after this string of heady gains, the stock remains attractive, said Erin Gibbs, portfolio manager at S&P Global.
"We like [Boeing] as a long term holding, strong cash flows with a productive lobbying in the current administration of Washington," Gibbs wrote in an email to CNBC on Thursday. "But [we] warn, valuations could easily compress from here if sentiment changes."
Valuations for defense stocks as an industry group have expanded significantly this year, Gibbs said. And while Boeing is expecting to log 38 percent earnings per share growth this year, next year's growth is expected to come in at 8 percent, before ramping up again in 2019.
Still, she adds that "many factors, including Washington spending, could change those estimates."
Gibbs, who manages portfolios that hold Boeing, pointed to the company's recent favorable outcome in a ruling from the U.S. Commerce Department as an important victory.
The International Trade Commission this week said it would impose a triple-digit tariff on the import of Bombardier C Series jets from Canada; the Canadian company called the tax "absurd and divorced from the reality about the financing of multibillion-dollar aircraft programs."
In a note to clients last week, Drexel Hamilton analyst Pete Skibitski raised his target price on Boeing to $297 per share from $285; his new target implies nearly 17 percent upside from its current share price. He rates the stock a buy.
The analyst wrote that his bullish view was due in part to the energy he felt from a recent annual investor conference.
"It felt like the buy-side/sell-side vibe at the conference was pretty positive. There's less to question/criticize internally at Boeing this year vs. the past, it seems to us," he wrote in a note entitled "The Story Isn't Over - Positive Vibe from the Palmetto State" referring to the nickname for South Carolina.
Shares of Boeing were trading slightly lower Friday afternoon, at $254.02 per share.