The time span for Flights from London to Newark Liberty International (Round-trip) as offered by KAYAK which is part of The Priceline Group is as follows:

Flights from London to Newark Liberty International (Round-trip)

Depart: Sat Oct 15 2016 Return: Mon Oct 24 2016 Trip spans 10 days
Airline: Icelandair
LGW→EWR10h 55m 1 stop
EWR→LGW10h 00m 1 stop

Depart: Fri Oct 14 2016 Return: Mon Nov 21 2016 Trip spans 39 days
Airline: SWISS
LCY→EWR12h 45m 1 stop
EWR→LCY12h 55m 1 stop

Depart: Sat May 21 2016 Return: Sun May 22 2016 Trip spans 2 days
Airline: Air Canada
LHR→EWR10h 12m 1 stop
EWR→LHR9h 50m 1 stop

Depart: Sun Oct 30 2016 Return: Sun Nov 6 2016 Trip spans 8 days
Airline: Austrian Airlines
STN→EWR28h 25m 1 stop
EWR→STN15h 20m 1 stop

Depart: Sat Oct 29 2016 Return: Sun Nov 6 2016 Trip spans 9 days
Airline: Virgin Atlantic
LHR→EWR7h 45m nonstop
EWR→LHR7h 25m nonstop

Depart: Wed Apr 27 2016 Return: Tue May 10 2016 Trip spans 14 days
Airline: KLM
LHR→EWR17h 09m 2 stops
EWR→LHR11h 41m 1 stop

Depart: Mon Oct 31 2016 Return: Sun Nov 20 2016 Trip spans 21 days
Airline: United
LHR→EWR11h 40m 1 stop
EWR→LHR11h 00m 1 stop

Depart: Wed Jul 13 2016 Return: Mon Jul 18 2016 Trip spans 6 days
Airline: TAP Portugal
LGW→EWR34h 25m 1 stop
EWR→LGW10h 40m 1 stop

Depart: Sun Sep 18 2016 Return: Sun Sep 25 2016 Trip spans 8 days
Airline: Icelandair
LGW→EWR10h 50m 1 stop
EWR→LGW10h 00m 1 stop

Depart: Mon Jul 11 2016 Return: Mon Jul 18 2016 Trip spans 8 days
Airline: British Airways
LCY→EWR35h 30m 2 stops
EWR→LCY18h 05m 2 stops

Depart: Sat Jun 4 2016 Return: Sun Jun 5 2016 Trip spans 2 days
Airline: Air Canada
LHR→EWR12h 02m 1 stop
EWR→LHR9h 50m 1 stop

Depart: Sat Jul 30 2016 Return: Sun Aug 7 2016 Trip spans 9 days
Airline: SAS
LHR→EWR13h 40m 1 stop
EWR→LHR14h 40m 1 stop

Depart: Mon Jul 25 2016 Return: Mon Aug 22 2016 Trip spans 29 days
Airline: Major Airline
LHR→EWR8h 05m nonstop
EWR→LHR7h 05m nonstop

Depart: Sat Aug 27 2016 Return: Sat Sep 10 2016 Trip spans 15 days
Airline: Virgin Atlantic
LHR→EWR7h 45m nonstop
EWR→LHR7h 05m nonstop

Depart: Tue Oct 11 2016 Return: Sat Oct 15 2016 Trip spans 5 days
Airline: Icelandair
LGW→EWR10h 50m 1 stop
EWR→LGW10h 00m 1 stop

Depart: Fri Jun 10 2016 Return: Mon Jun 13 2016 Trip spans 4 days
Airline: Austrian Airlines
LHR→EWR8h 05m nonstop
EWR→LHR7h 10m nonstop

Depart: Tue May 3 2016 Return: Tue May 31 2016 Trip spans 29 days
Airline: KLM
LCY→EWR13h 01m 1 stop
EWR→LCY11h 55m 1 stop

Depart: Fri Sep 16 2016 Return: Sun Sep 25 2016 Trip spans 10 days
Airline: SWISS
LCY→EWR12h 45m 1 stop
EWR→LCY16h 40m 1 stop

Depart: Sat Aug 20 2016 Return: Wed Oct 5 2016 Trip spans 47 days
Airline: United
LHR→EWR13h 55m 1 stop
EWR→LHR13h 05m 1 stop

Depart: Mon Sep 5 2016 Return: Mon Sep 19 2016 Trip spans 15 days
Airline: Virgin Atlantic
LHR→EWR7h 45m nonstop
EWR→LHR7h 05m nonstop
get more details so find link
kayak.com/flight-routes/London-LON/Newark-Liberty-International-EWR