Surely not, indeed!
"After 18 months (from memory) [Buhari] stood down and elections were held."
No, Buhari was ousted by General Babangida, and then a long and very damaging period of dictatorship ensued, particularly under Sani Abacha. I think that this commentator is mixing Buhari up with Obasanjo, who did step down to be replaced by a civilian government, one ousted by a coup involving Buhari. Buhari lost power in another coup; he did not step down, nor did Nigeria return to civilian rule post-Buhari.
"Early days, but I have a feeling that under this President, Nigeria has an opportunity to advance and bring infrastructure up to speed, including aviation." To have this "feeling" probably requires that you know rather little about Buhari's previous form, as you seem to, despite your "good many contacts in Nigeria." This is not "new territory" for Nigeria, not at all.