Without Churchill, UK might, or might not, have tried to make peace with Germany, after the defeat of France, since Hitler certainly offered it.
What Hitler stood no chance of doing was forcing UK to make peace by a successful landing in Britain.
A German attempt at a paratroop landing would have firstly been massacred by RAF Fighter Command, but even if a large number of troops managed to land -unlikely in itself- they would have fared even worse than they actually did in Crete, where they faced almost no air opposition and no armoured vehicles, and where they nearly lost. Remember Germany had one airborne Divsion only in 1940.
Even if the airborne troops don't get shot down on route and then, somehow manage to capture a port, how do the Germans reinforce them with next to no navy, facing what, in 1940, was still the joint largest navy in the world?
"Royal Navy Warship Strength
The Royal Navy, still the largest in the world in September 1939, included:
15 Battleships & battlecruisers, of which only two were post-World War 1. Five 'King George V' class battleships were building.
7 Aircraft carriers. One was new and five of the planned six fleet carriers were under construction. There were no escort carriers.
66 Cruisers, mainly post-World War 1 with some older ships converted for AA duties. Including cruiser-minelayers, 23 new ones had been laid down.
184 Destroyers of all types. Over half were modern, with 15 of the old 'V' and 'W' classes modified as escorts. Under construction or on order were 32 fleet destroyers and 20 escort types of the 'Hunt' class.
60 Submarines, mainly modern with nine building.
45 escort and patrol vessels with nine building, and the first 56 'Flower' class corvettes on order to add to the converted 'V' and 'W's' and 'Hunts'. However, there were few fast, long-endurance convoy escorts.
Commonwealth Navies
Included in the Royal Navy totals were:
Royal Australian Navy - six cruisers, five destroyers and two sloops;
Royal Canadian Navy - six destroyers;
Royal Indian Navy - six escort and patrol vessels;
Royal New Zealand Navy, until October 1941 the New Zealand Division of the Royal Navy - two cruisers and two sloops."
http://www.naval-history.net/WW2CampaignRoyalNavy.htm
The manpower of the Royal Navy and Royal Marines stood at over 200,000 in 1939.
By contrast even before losses off Norway, etc in 1939 Germany had
2 Battle Cruisers ( with 2 Battleships building)
3 'Pocket Battleships'
8 Cruisers (with 1 building)
22 Destroyers (with 12 building)
20 Torpedo boats with 12-14 building
57 submarines
The Germans had a number of other ships in the early stages of construction, but not much useful work was done on them after the outbreak of war.
By 1940 from this initially small force the Germans had already lost one 'Pocket Battleship', three cruisers and 10 Destroyers, ie roughly a third of their naval forces at the outbreak of war.