Five islands will be destroyed as part of the airport project.
Haris Abdul Gafoor was stabbed to death last year.
The man was stabbed eight times on Tuesday morning.
The court did not give a reason for throwing the charges out.
It is almost four years since Ahmed Rilwan disappeared.
The proposed airport could be unusable because of flood risks.
The arrests were made in connection with the rape of a 16-year-old girl in Malé last month.
The seven defendants pleaded not guilty at Thursday's pre-trial hearing.
The president's spokesman denied allegations that he has not disclosed personal finances for four years.
Hassan Saeed was suspended for calling two High Court judges "the most corrupt judges in the world."
Defence lawyers argued the murder charges were unclear.
There were 355 sexual offence cases reported to police in 2017. Figures for 2018 are unavailable.
There are concerns about voter manipulation, transparency and confusion caused by the changes.
No reason was given for the cancellation by court staff.
There has been anger over changes to how and where Maldivians can vote in September.
A cornetfish was embedded into the man's neck.
Diving is considered 'dangerous' and an activity for men, not women.
