Techniques pertaining to efficient and flexible frequency domain (FD) aggregated physical-layer protocol data unit (FD-A-PPDU) with the same and/or mixed WiFi generations transmission are described. An apparatus (e.g., a station (STA)) performs (810) a wireless communication by: (i) transmitting (812) a FD-A-PPDU or (ii) receiving (814) the FD-A-PPDU. The wireless communication is performed in a 160MHz, 240MHz, 320MHz, 480MHz or 640MHz bandwidth with 80MHz being a minimum size of each of multiple PPDUs of the FD-A-PPDU. The FD-A-PPDU may be a 160MHz, 240MHz, 320MHz, 480MHz or640MHz FD-A-PPDU. The FD-A-PPDU may include PPDUs having a same PPDU format or different PPDU formats of different WiFi generations and utilizing a minimum size of 80MHz non-overlapping frequency subblocks as a base building block.