Introducing the Lockheed Martin F-21...

[AS.12]

The F-21A Kfirs were leased aircraft and were returned after being used
for a few years, I wouldn't be surprised if the designation was primarily
for bookkeeping purposes.

The fact that the Kfirs were leased was irrelevant, F-21A was an official MDS issued by the DoD, it was't just a number made up on the flightline for filling-in forms.  It was official enough to knock the first ATF designation along to YF-22!

It wouldn't have taken more than ten minutes to choose a better 'new name' for the F-16.  Even F-25 would have sufficed, since that's what the X-35 was supposed to become...

I might have pardoned LM had this been the early 1990s, but in this era of instant-information there is really no excuse for being so sloppy and lazy.  I'm glad that the Flight article called them out on the reuse.

[zenrat]

I don't see the problem.  It's only a number.  Names get reused all the time.

[NARSES2]

Anyhow, designations have been cancelled and reused in the past, and at the
moment L-M can call it anything they want, if they apply to make it an official
designation it'll be up to the DoD to say yeah or nay.

My thoughts as well. Calling it F.21 probably makes it sound more modern and "sexy" to their ears and that is what marketing types are all about, when not doing "retro" of course 

[jcf]

The F-21A Kfirs were leased aircraft and were returned after being used
for a few years, I wouldn't be surprised if the designation was primarily
for bookkeeping purposes.

The fact that the Kfirs were leased was irrelevant, F-21A was an official MDS issued by the DoD, it was't just a number made up on the flightline for filling-in forms.  It was official enough to knock the first ATF designation along to YF-22!

It wouldn't have taken more than ten minutes to choose a better 'new name' for the F-16.  Even F-25 would have sufficed, since that's what the X-35 was supposed to become...

I might have pardoned LM had this been the early 1990s, but in this era of instant-information there is really no excuse for being so sloppy and lazy.  I'm glad that the Flight article called them out on the reuse.

O brother, none of it is written in stone nor is it holy writ.

Again it's not a flipping official designation, at the moment, and L-M
can market it under any damned name they choose.

The Flight article didn't call them out, it simply mentioned
the reuse without taking a position one way or other.