Well, I haven't been here for a while, so...
I see the question is 'been to', not 'flown from'. So I could add a few more, I suppose
UK & CI
EDI Edinburgh Turnhouse
EXT Exeter International
GCI Guernsey
GLA Glasgow Abbotsinch
JER Jersey
LBA Leeds Bradford
LCY London City
LGW London Gatwick
LHR London Heathrow
LTN London Luton
MAN Manchester Ringway
NCL Newcastle Woolsington
NQY Newquay St Mawgan
NWI Norwich Horsham St Faith
PZE Penzance Heliport (Now Closed)
STN London Stansted
TSO Tresco Heliport
EMA Nottingham East Midlands
SEN London Southend
BHX Birmingham
PIK Glasgow Prestwick (Not Flying)
Ireland
DUB Dublin
SNN Shannon
France
CDG Paris Roissy Charles de Gaulle
MPL Montpellier Mediterranee
ORY Paris Orly
RHE Reims Champagne (Now Closed to Commercial Traffic)
SXB Strasbourg Entzheim
FNI Nimes Ales Camargue Cevennes
BZR Beziers Cap d'Agde
NCE Nice Cote D'Azur
UIP Quimper Pluguffan (Not Flying)
BVA Beauvais Tillé (Not Flying)
MLH See BSL
Spain
BCN Barcelona El Prat
BIO Bilbao Sondika
MAD Madrid Barajas
MAH Mahon Menorca
PMI Palma de Mallorca
ALC Alicante Elche
AGP Malaga
Portugal
FAO Faro
LIS Lisbon Portela
OPO Porto Francisco Sa Carneiro
Belgium
BRU Brussels Zaventem
Netherlands
AMS Amsterdam Schiphol
RTM Rotterdam Zestienhoven (Not Flying)
Luxembourg
LUX Luxembourg Findel
Germany
DUS Dusseldorf
FRA Frankfurt Main
HAM Hamburg Fuhlsbuttel
MUC Munich Franz Josef Strauss
TXL Berlin Tegel
SXF Berlin Schonefeld
STR Stuttgart Echterdingen (Not Flying)
DRS Dresden Klotzsche (Not Flying)
THF Berlin Tempelhof (Not Flying, Now Closed)
Switzerland
BRN Bern Belp
BSL Basel Mulhouse Freiburg EuroAirport
GVA Geneva Cointrin
ZRH Zurich Kloten
Austria
GRZ Graz Thalerhof
SZG Salzburg WA Mozart
VIE Vienna Schwechat
Italy
FCO Rome Fiumincino
LIN Milan Linate
MXP Milan Malpensa
TRN Turin Caselle
TSF Treviso Sant'Angelo
VBS Brescia Gabriele d'Annunzio
VRN Verona Catullo
PSA Pisa Galileo Galilei
Denmark
CPH Copenhagen Kastrup
JAV Ilulissat (Jakobshavn)
JCH Aasiaat (Christianshåb)
JEG Qasigiannguit (Egedesminde)
SFJ Kangerlussuaq (Sondre Stromfjord)
Norway
BGO Bergen Flesland
OSL Oslo Gardermoen
Sweden
ARN Stockholm Arlanda
MMX Malmo Sturup
Finland
HEL Helsinki Vantaa
Poland
WAW Warsaw Okecie
Czech Republic
PRG Prague Ruzyne
Hungary
BUD Budapest Ferihegy
Croatia
ZAG Zagreb Pleso
Romania
OTP Bucharest Otopeni
TSR Timisoara Traian Buia
Bulgaria
VAR Varna
Turkey
IST Istanbul Ataturk
Latvia
RIX Riga
Russia
SVO Moscow Sheremetyevo
Uzbekistan
TAS Tashkent
India
BOM Mumbai Chhatrapati Shivaji
COK Cochin Nedumbassery
DEL Delhi Indira Gandhi
HYD Hyderabid Rajiv Gandhi
TRV Trivandrum
MAA Chennai Meenambakkam
BLR Bengaluru Kempegowda
BLR Bengaluru Hindustan Airport (Now Closed)
CCU Kolkata Netaji Subhas Chandra Bose
China
PVG Shanghai Pudong
DLU Dali
KMG Kunming Wujiaba
KWL Guilin Liangjiang
LJG Lijiang Sanyi
HKG Hong Kong Chek Lap Kok
Thailand
BKK Bangkok Suvarnabhumi
DMK Bangkok Don Mueang
HDY Hat Yai
KBV Krabi
Singapore
SIN Singapore Changi
South Korea
ICN Seoul Incheon
GMP Seoul Gimpo (Not Flying)
Malaysia
KUL Kuala Lumpur Sepang
Japan
FUK Fukuoka Itazuke
ITM Osaka Itami
KIX Osaka Kansai
NRT Tokyo Narita
Philippines
CEB Mactan-Cebu
MNL Manila Ninoy Aquino
TAG Tagbilaran
Australia
ASP Alice Springs
CNS Cairns
SYD Sydney Kingsford Smith
New Zealand
AKL Auckland
CHC Christchurch Harewood
KKE Kerikeri Bay of Islands
MFN Milford Sound
ZQN Queenstown
Canada
YUL Montreal Dorval
YYZ Toronto Pearson
ATL Atlanta Hartsfield
USA
BLD Boulder City
BOS Boston Logan
BWI Baltimore Washington
CLD Carlsbad McLellan-Palomar (Not Flying, Now Closed to Commercial Traffic)
DFW Dallas Fort Worth
DTW Detroit Wayne County
EWR Newark Liberty
GCN Grand Canyon National Park
HYA Hyannis Barnstable
IAD Washington Dulles
JFK New York JF Kennedy
LAS Las Vegas McCarran
LAX Los Angeles
LGA New York LaGuardia
MDW Chicago Midway
MIA Miami
ORD Chicago O'Hare
SAN San Diego Lindbergh Field
SFO San Francisco
Mexico
MEX Mexico City Benito Juarez
Peru
CUZ Cusco Velasco Astete
LIM Lima Jorge Chavez
Bolivia
LPB La Paz El Alto
VVI Santa Cruz Viru Viru
Netherlands Antilles
CUR Curacao Hato
Morocco
CMN Casablanca Mohammed V
RAK Marrakech Ras Al Khaimah
Qatar
DOH Doha
Sri Lanka
CMB Colombo Bandaranaike