Police have insisted that interviewing the Shoreham air disaster pilot remains "an integral part" of their investigation - despite having not yet questioned him.
Andrew Hill was left fighting for his life after the Hawker Hunter plane he was flying failed to pull out of a loop-the-loop stunt and plummeted on to the A27 in West Sussex.
He was released from an undisclosed specialist hospital more than one month ago but has yet to be questioned by investigators.
Detective Chief Inspector Paul Rymarz who is leading the Sussex Police investigation into the air show crash said: "The interview of the pilot forms an integral part of the police investigation, but at this time his fitness for interview has not been confirmed.
"Additionally, we are still in an evidence-gathering stage, with appropriate expert assistance, as we need to fully understand every element of what is a very complex subject in order to gain maximum benefit from that interview.
"The families of the victims have been updated as to the reasons why the pilot has not yet been interviewed," he added.
Family and friends of the 11 victims of the fatal crash have reportedly voiced concerns about the delay in questioning Mr Hill.
Giovanna Chirico, who was engaged to 54-year-old victim Mark Trussler from Worthing, told the BBC families needed answers and now faced a "frustrating waiting game".
"We all lost our loved ones," she said. "And he's come out of a plane crash and is walking around and is still with his family."
The best friend of victim Matt Jones, 24, Stevie Johnson, added that once the pilot is interviewed "it will be easier for us to all come together and grieve".
A friend of Mr Hill's told the broadcaster he believed the delay in the police interview would be to do with the pilot's memory or state of mind.
An interim report by the Air Accidents Investigation Branch (AAIB) found ''no abnormal indications'' during the Hawker Hunter flight.
Investigators also said cockpit cameras showed the 1950s jet ''appeared to be responding to the pilot's control inputs''.
The victims who died were: wedding chauffeur Maurice Abrahams, 76, from Brighton; retired engineer James Graham Mallinson, 72, from Newick, near Lewes; window cleaner and general builder Mark Trussler, 54, from Worthing; cycling friends Dylan Archer, 42, from Brighton, and Richard Smith, 26, from Hove; NHS manager Tony Brightwell, 53, from Hove; grandfather Mark Reeves, 53, from Seaford; Worthing United footballers Matthew Grimstone and Jacob Schilt, both 23; personal trainer Matt Jones, 24; and Daniele Polito, 23, from Worthing.
The inquest into their deaths was opened and adjourned in September by West Sussex senior coroner Penelope Schofield. A pre-inquest review will take place on March 22.