Under Section 18(1)(a) and (b), officers/employees of the erstwhile IAAI and NAA, upon the appointed day, respectively become officers/employees of:

Section 18(1) preserves an initial administrative distinction even after the merger: IAAI employees become officers/employees of the 'International Airports Division' of the Authority, while NAA employees become officers/employees of the 'National Airports Division' of the Authority - rather than being merged into a single undifferentiated cadre immediately. This divisional structure reflects the practical reality that full personnel integration takes time, even though the underlying undertakings vest completely and immediately under Section 13. Only after the one-year (extendable to two-year) option period under Section 18(2) lapses do transferred employees become fully subject to the Authority's own unified service rules under Section 18(7).