The family of 19-year-old Harry Dunn say they held a "promising" meeting with their MP, Andrea Leadsom.
They met following the US Secretary of State’s decision to reject an extradition request for Anne Sacoolas, the driver suspected of killing the teenager.
Harry Dunn’s father Tim Dunn said of the meeting with Ms Leadsom: "Some things we agree on and some things we don’t agree on.
"But I feel like she’s behind us, I really do."
Harry Dunn was killed when his motorbike collided with a car outside RAF Croughton, a base used by the US military in Northamptonshire, last August.
The Crown Prosecution Service announced plans to charge Anne Sacoolas, 42, with causing his death by dangerous driving in December.
Mrs Sacoolas claimed diplomatic immunity following the crash and was able to return to her home country, sparking an international controversy.
In a statement following the extradition request decision, a spokeswoman for the Home Office said: "We are disappointed in this decision, which appears to be a denial of justice.
"We are urgently considering our options."
Speaking after a meeting with Harry Dunn’s family, Business Secretary Ms Leadsom said: "We’ve been talking about the frustrating news that the extradition was refused yesterday by the US government.
"Obviously Harry’s family are disappointed and very upset by that, but equally very determined that the driver of the car that killed Harry Dunn should be brought back to the United Kingdom to face justice.
"We are absolutely united in our determination to get justice for Harry."
In a statement released on behalf of the suspect in December, Mrs Sacoolas’s lawyers said: "Anne will not return voluntarily to the United Kingdom to face a potential jail sentence for what was a terrible but unintentional accident."
Lawyers acting on behalf of the Dunn family have said it is the first time in the 100-year history of the extradition treaty that such a request has been turned down by the US.
Earlier this week, Harry Dunn's parents told Forces News they had written to the Defence Secretary requesting an urgent review into road safety around American military bases.
It followed an announcement by Northamptonshire Police Chief Constable Nick Adderley stating he would fund driver training for all staff at the base from 12 March.