The strike is costing Boeing an estimated $1 billion a month, and new CEO Kelly Ortberg is working to keep the company afloat. Boeing is raising up to $25 billion through stock and debt offerings. It's arranging a $10 billion credit agreement with major lenders amid a production and regulatory crisis.

There was substantial upside if one bought Boeing stock” during prior strikes in 1989, 1995 and 2005, an analyst says, though a 2008 strike that coincided with the Great Recession was an outlier.

Boeing’s (NYSE:BA) stock rose 5.5% as regular trading opened Monday after the planemaker said it had reached a tentative agreement with its machinists union that would end a five-week strike. While getting employees back to work is positive for Boeing (BA),