“Fulcrums were 2 weeks there and the operation was surrounded by secrecy to the extent that from the moment of departure from Poland until return,
insignia and markings that could help to identify them were removed.”

Hmm, can’t think of many MiG-29 operators with a square “roundel” (or is that a squarel?).
More overpainting required I think…

So it seems the Czech Air Force has a new serial system?
The C.295s had serials not related to their c/n (0452/0455)
This Enstrom is c/n 5241 I think…

“Are you volunteering the massive time and considerable expense needed to create and maintain such a list?”

No, because this subject is of no particular interest to me. It was just to illustrate what is possible. Like everything, it needs a lot of time and effort, but could be built up slowly, in much the same way as Joe Baugher’s US military serial lists are.
Too many researchers are leaving us these days, and in a lot of cases their material is dying with them because no arrangements have been made to safeguard their research…

No, they did not routinely change serials for security reasons, that is a myth. Sometimes the first digit was changed, but the last two digits remained constant. This first digit usually changed when an aircraft was upgraded. For example, CH-53 c/n 65127 started as 414, then became 714, then 914 as various upgrades were performed.
I can think of hardly any cases when the actual serial was changed. Some examples:
AH-64As when they were converted to AH-64D got new serials
F-16C 236 became 140 (special serial for 140 Sqn)
F-16C 535 became 101 (special serial for 101 Sqn)
The three RF-4E(S) changed serials to 492, 498, 499 (special serials for recce aircraft)

It is true to say that the Fougas received new serials when they were converted to Tzukits, but this would have had nothing to do with security. They were simply numbered from 01 to 86! Here’s what I have.
The 5__ serials were from Israeli assembled kits (except for 560 ex France). 6__ serials are ex German.
Tzukit c/n is 0__ (last two digits of serial). C/n shown is Fouga c/n, or German c/n (first 62 German aircraft also have Fouga c/n)
501 (c/n 46, ex 264)
402
603 (c/n D128, ex 119)
604
505 (c/n 45, ex 261)
606 (c/n D87, ex 088)
607 (c/n D64, ex 032)
608
609 (c/n D160)
610 (c/n D223, ex 123)
611 (c/n D118, ex 198?)
612
613 (c/n D161, ex 193)
614 (c/n D17/90, ex 021)
615 (c/n D24/106, ex 047)
616 (c/n D19/92, ex 031)
617 (c/n D33/127, ex 049)
618 (c/n D184, ex 114)
619 (c/n D8/73, ex 023)
620 (c/n D35/129, ex 041)
521 (c/n 05, ex 219)
622 (c/n D143, ex 110)
623 (c/n D167, ex 126)
524 (c/n 13)
625 (c/n D119, ex 103)
626 (c/n D32/121)
627 (c/n D149, ex 095)
528 (c/n 08, ex 272)
629 (c/n D23/105, ex 044)
630 (c/n D181, ex 152)
631 (c/n D179)
632 (c/n D146, ex 121)
533 (c/n 35, ex 290)
634 (c/n D132, ex 109)
635 (c/n D15/87, ex 022)
536 (c/n 22, ex 230)
637 (c/n D152, ex 122)
538 (c/n 14, ex 278)
639 (c/n D214, ex 129)
540 (c/n 16, ex 280)
541 (c/n 39, ex 234)
642 (c/n D16/88, ex 043)
643 (c/n D225, ex 157)
644 (c/n D144, ex 194)
645 (c/n D190, ex 153)
546 (c/n 15, ex 279)
647 (c/n D107, ex 170)
648 (c/n 96, ex 163, tender Jul10)
549 (c/n 18, ex 226, tender Jul10)
650 (c/n D__/50)
651 (c/n D232, ex 154)
652 (c/n D6/71, ex 045)
553 (c/n 19, ex 227)
654 (c/n D103, ex 116)
555 (c/n 02, ex 216)
556 (c/n 17, ex 225)
557 (c/n 29, ex 209, tender Jul10)
558 (c/n 43, ex 291, tender Jul10)
659 (c/n D111, ex 102)
560 (c/n 176, ex 285)
661 (c/n D83, ex 058)
562 (c/n 42, ex 288)
563 (c/n 25, ex 205, tender Jul10)
564 (c/n 034, ex 212)
665 (c/n D127, ex 105)
666 (c/n D75, ex 125)
667 (c/n D82, ex 101)
668 (c/n D25/107, ex 042)
569 (c/n 06, ex 220)
670 (c/n D138, ex 197)
571 (c/n 40, ex 287)
672 (c/n D158/72, ex 112)
673 (c/n D40/142, ex 038)
674 (c/n D91/74, ex 115)
675
676 (c/n D13/82, ex 050, tender Jul10)
677 (c/n D153, ex 111)
678 (c/n D205, ex 199)
579 (c/n 44, ex 292)
680 (c/n D5/65, ex 040)
681 (c/n D105, ex 168)
682 (c/n D159, ex 196)
683 (c/n D36/132, ex 048)
584 (c/n 004, ex 218)
685 (c/n D234, ex 103)
686 (c/n D189, ex 128)

The next Norwegian Merlin (0270) was delivered out of Yeovil this morning.

That looks like a PA-23 Aztec to me.

That is an Egyptian aircraft….