From 18 to 31 May, the frequency will increase from the current two flights a week to three flights per week.
This information could be useful which I found for TAP flights from Lisbon over the coming months.
TAP Air Portugal in the last few weeks filed preliminary schedule for the period of 18MAY20 – 31JUL20. The Star Alliance carrier currently plans gradual service resumption from 18MAY20, with flights available for reservation under flight number range TP2000 – 2999 series, except selected routes.
As of 0720GMT 30APR20, preliminary operation for 18MAY20 – 31JUL20 as follows
Hard to say how accurate this list is, and things are changing daily, but it could be useful for some.
Lisbon – Abidjan eff 01JUL20 4 weekly
Lisbon – Accra – Sao Tome eff 02JUL20 2 weekly A321neo
Lisbon – Amsterdam eff 19MAY20 3 weekly Embraer E190 (7 weekly from 01JUN20, 2 daily from 01JUL20)
Lisbon – Barcelona eff 18MAY20 1 daily Embraer E190/195 (2 daily from 01JUN20, 3 daily A319/320 from 01JUL20)
Lisbon – Belem eff 04JUN20 2 weekly A321neo
Lisbon – Belo Horizonte eff 22MAY20 1 weekly A330-900neo (2 weekly from 01JUN20, 3 weekly from 02JUL20)
Lisbon – Berlin Tegel eff 01JUL20 1 daily A320
Lisbon – Bilbao eff 01JUL20 1 daily ATR72
Lisbon – Bissau eff 23MAY20 1 weekly E190 (A319 from 06JUN20, 2 weekly A320neo from 02JUL20)
Lisbon – Bordeaux eff 01JUL20 1 daily Embraer E190
Lisbon – Boston eff 21MAY20 1 weekly A321neo (3 weekly from 02JUN20, 5 weekly from 02JUL20)
Lisbon – Brasilia eff 02JUN20 2 weekly A330-900neo (3 weekly from 01JUL20)
Lisbon – Brussels eff 18MAY20 3 weekly Embraer E190 (1 daily E190/195 from 01JUN20, 1 daily A319/320 from 01JUL20)
Lisbon – Casablanca eff 01JUN20 5 weekly Embraer E190 (E190/195/A319 from 01JUL20)
Lisbon – Conakry eff 01JUL20 3 weekly A320neo
Lisbon – Copenhagen eff 01JUL20 1 daily A319/320/320neo
Lisbon – Dakar eff 01JUL20 1 daily A320neo
Lisbon – Dublin eff 01JUL20 2 daily A319
Lisbon – Dusseldorf eff 01JUL20 1 daily A319/320
Lisbon – Faro eff 01JUL20 3 daily A319/320/320neo/E190/E195
Lisbon – Fortaleza eff 05JUN20 2 weekly A330-900neo (3 weekly from 01JUL20)
Lisbon – Frankfurt eff 18MAY20 2 weekly Embraer E190 (1 daily A319 from 01JUN20, 2 daily A319/320/320neo from 01JUL20)
Lisbon – Funchal eff 18MAY20 1 daily E190 (2 daily E190/E195/A319 from 01JUN20, 3 daily from 01JUL20)
Lisbon – Geneva eff 01JUN20 1 daily A319/Embraer E190 (2 daily A319/320/320neo from 01JUL20)
Lisbon – Gran Canaria eff 01JUN20 3 weekly A319/E190 (1 daily E195/A319 from 01JUL20)
Lisbon – Hamburg eff 01JUL20 1 daily A319/320/320neo
Lisbon – Helsinki eff 06JUN20 1 weekly A319 (3 weekly A320neo from 02JUL20)
Lisbon – Ilha do Sal eff 22MAY20 3 weekly Embraer E190 (A320neo from 03JUL20)
Lisbon – London Heathrow eff 18MAY20 1 daily Embraer E190 (2 daily E190/A319 from 01JUN20, 5 daily E190/A320/320neo from 01JUL20)
Lisbon – Luanda eff 20MAY20 2 weekly A321neo (5 weekly A330-900neo from 01JUN20)
Lisbon – Luxembourg eff 03JUL20 3 weekly A319
Lisbon – Lyon eff 01JUL20 2 daily Embraer E190/195
Lisbon – Maceio eff 26JUN20 2 weekly A321neo (New route previously scheduled from 12JUN20. Reservation is available with regular flight numbers)
Lisbon – Madrid eff 18MAY20 1 daily Embraer E190 (2 daily E190/A319 from 01JUN20, 3 daily A319/320/320neo from 01JUL20)
Lisbon – Malaga eff 01JUL20 1 daily Embraer E190/195
Lisbon – Manchester eff 01JUL20 1 daily A319
Lisbon – Maputo eff 03JUN20 2 weekly A330-900neo
Lisbon – Marrakech eff 01JUN20 5 weekly Embraer E190 (1 daily E195/A319 from 01JUL20)
Lisbon – Marseille eff 01JUL20 2 daily Embraer E190
Lisbon – Miami eff 02JUN20 3 weekly A330-900neo (1 daily from 02JUL20)
Lisbon – Milan Malpensa eff 01JUN20 1 daily Embraer E195 (2 daily from E190/E195/A319/320/320neo from 01JUL20)
Lisbon – Montreal eff 26JUN20 6 weekly A321neo (Reservation is available with regular flight numbers)
Lisbon – Munich eff 01JUN20 1 daily A319 (A319/320 from 01JUL20)
Lisbon – Natal eff 04JUL20 2 weekly A321neo
Lisbon – Newark eff 18MAY20 2 weekly A321neo (5 weekly from 03JUN20, 1 daily from 01JUL20)
Lisbon – Nice eff 01JUL20 2 daily Embraer E190/195
Lisbon – Oslo eff 01JUL20 1 daily A320neo/321neo
Lisbon – Paris CDG eff 19MAY20 1 daily Embraer E190 (2 daily E190/195 from 01JUN20, 3 daily A319/320 from 01JUL20)
Lisbon – Ponta Delgada eff 18MAY20 1 daily Embraer E190 (E195/A320neo from 01JUN20, A320/320neo from 01JUL20)
Lisbon – Porto eff 18MAY20 11 weekly ATR72/E190/E195/A319/321neo (18 weekly from 01JUN20, 29 weekly from 01JUL20)
Lisbon – Porto Santo eff 05JUN20 2 weekly Embraer E190 (3 weekly from 03JUL20)
Lisbon – Praia eff 18MAY20 2 weekly Embraer E190 (5 weekly from 03JUN20, 1 daily A320neo from 01JUL20)
Lisbon – Prague eff 02JUL20 3 weekly A320
Lisbon – Recife eff 21MAY20 1 weekly A321neo (3 weekly from 01JUN20, 4 weekly A330-900neo from 03JUL20)
Lisbon – Rio de Janeiro Galeao eff 21MAY20 1 weekly A330-900neo (3 weekly from 02JUN20, 5 weekly from 01JUL20)
Lisbon – Rome eff 01JUN20 2 daily A319 (3 daily A319/320/320neo)
Lisbon – Salvador da Bahia eff 04JUN20 2 weekly A330-900neo (3 weekly from 01JUL20)
Lisbon – Santiago de Compostela eff 01JUL20 1 daily ATR72 (New route initially 1 daily open for booking, 2 daily from 01AUG20. Reservation is available with regular flight numbers)
Lisbon – Sao Paulo Guarulhos eff 21MAY20 2 weekly A330-900neo (1 daily from 01JUN20, 10 weekly from 01JUL20)
Lisbon – Sao Vicente eff 22MAY20 1 weekly Embraer E190 (3 weekly A320neo from 02JUL20)
Lisbon – Seville eff 01JUL20 2 daily Embraer E190
Lisbon – Stockholm Arlanda eff 02JUN20 5 weekly A319 (7 weekly A320/320neo from 01JUL20)
Lisbon – Tel Aviv eff 03JUN20 3 weekly A320neo (4 weekly A321neo from 02JUL20)
Lisbon – Tenerife South eff 01JUN20 3 weekly Embraer E190 (1 daily A319 from 01JUL20)
Lisbon – Terceira eff 22MAY20 2 weekly Embraer E190 (3 weekly from 01JUN20, 1 daily A319/320 from 01JUL20)
Lisbon – Toronto eff 22MAY20 1 weekly A321neo (3 weekly A330-900neo from 01JUL20)
Lisbon – Toulouse eff 01JUL20 2 daily Embraer E190/195
Lisbon – Valencia eff 01JUL20 1 daily ATR72
Lisbon – Vienna eff 01JUL20 1 daily A320/320neo/321neo
Lisbon – Warsaw A320 scheduled on 24MAY20 and 07JUN20 (1 daily A320/320neo from 01JUL20)
Lisbon – Zurich eff 22MAY20 2 weekly Embraer E190 (1 daily E195 from 01JUN20, 2 daily A319/320/320neo from 01JUL20)
Ponta Delgada – Boston eff 22JUN20 4 daily A321neo (Service resumption previously scheduled from 04JUN20. Reservation is available with regular flight numbers)
Ponta Delgada – Toronto eff 25JUN20 2 weekly A321neo (Reservation is available with regular flight numbers)
Porto – Funchal eff 03JUL20 4 weekly A319
Porto – London Heathrow 01JUL20 – 30JUL20 1 daily Embraer E190 (Replacing 2 daily Porto – London Gatwick in July)
Porto – Paris CDG eff 04JUN20 2 weekly Embraer E190 (1 daily from 01JUL20)