Not sure how this will impact hiring:
Virgin Atlantic Airways (London) has tentatively scheduled the last Boeing 747-400 revenue flight for an arrival on April 18, 2016 in London. According to Airline Route, the last planned flight is currently flight VS 006 departing Miami at 9:50 pm (2150) on April 17, 2016 and arriving the next day (April 18) at London (Heathrow) at 11:30 am (1130).
I presume newhires will be directed to the A330/340 fleet vs. the 787 fleet as 400 pilots likely get moved to the 787.