Introductory flight

The Air Operations Regulation defines the term in Article 2(9):

‘introductory flight’ means any operation against remuneration or other valuable consideration consisting of an air tour of short duration for the purpose of attracting new trainees or new members, performed either by a training organisation referred to in Article 10a of Commission Regulation (EU) No 1178/2011 or by an organisation created with the aim of promoting aerial sport or leisure aviation;

Article 6(4a)(c) allows these flights under Part-NCO on conditions, including that "the aircraft is operated by the organisation on the basis of ownership or dry lease, that the flight does not generate profits distributed outside of the organisation, and that whenever non-members of the organisation are involved, such flights represent only a marginal activity of the organisation."

This is a different exception from cost sharing, which is Article 6(4a)(a). An introductory flight is run by an organisation; a cost-shared flight must be operated by a private individual, and passengers can pay only an equal share of the direct costs.

So the introductory flight exception isn't available to you as a private pilot acting on your own account. Taking a friend flying and splitting the direct costs is cost sharing; charging a fixed price for a pleasure flight is neither, unless it is an introductory flight run by a qualifying organisation within Article 6(4a)(c).