GAO report about the evolution of the Joint Strike Fighter (F35-JSF) program
Figure about Software growth, Estimated lines of code (millions)
ref: GAO-12-437, June 2012, page 19
And here some comments copied/pasted from the GAO report:

Software providing essential JSF capability has grown in size and complexity, and is taking longer to complete than expected. Late releases of software have delayed testing and training and added costs. Some capabilities have been deferred until later in development in order to maintain schedule.The lines of code necessary for the JSF’s capabilities have now grown to over 24 million—9.5 million on-board the aircraft. (By comparison, JSF has about 3 times more on-board software lines of code than the F-22A Raptor and 6 times more than the F/A-18 E/F Super Hornet.) This has added work and increased the overall complexity of the effort. The software on-board the aircraft and needed for operations has grown 37 percent since the critical design review in 2005. While software growth appears to be stabilizing, contractor officials report that almost half of the on-board software has yet to complete integration and test—typically the most challenging phase of software development. JSF software growth is not much different than other recent defense acquisitions, which have experienced from 30 to 100 percent growth in software code over time. However, the sheer number of lines of code for the JSF makes the growth a notable cost and schedule challenge. [The figure] shows increased lines of code for both airborne and ground systems.

GAO report about the evolution of the Joint Strike Fighter (F35-JSF) program

Figure about Software growth, Estimated lines of code (millions)

ref: GAO-12-437, June 2012, page 19

And here some comments copied/pasted from the GAO report:

Software providing essential JSF capability has grown in size and complexity, and is taking longer to complete than expected. Late releases of software have delayed testing and training and added costs. Some capabilities have been deferred until later in development in order to maintain schedule.

The lines of code necessary for the JSF’s capabilities have now grown to over 24 million—9.5 million on-board the aircraft. (By comparison, JSF has about 3 times more on-board software lines of code than the F-22A Raptor and 6 times more than the F/A-18 E/F Super Hornet.) This has added work and increased the overall complexity of the effort. The software on-board the aircraft and needed for operations has grown 37 percent since the critical design review in 2005. While software growth appears to be stabilizing, contractor officials report that almost half of the on-board software has yet to complete integration and test—typically the most challenging phase of software development. JSF software growth is not much different than other recent defense acquisitions, which have experienced from 30 to 100 percent growth in software code over time. However, the sheer number of lines of code for the JSF makes the growth a notable cost and schedule challenge. [The figure] shows increased lines of code for both airborne and ground systems.

(Source: )