Two divergences:
1936 - General Sanjurjo sensibly flies from Lisbon to Salamanca in the De Havilland Rapide rather than romantically taking Ansaldo's two-seater - is not killed in a crash.
1940 - Allied codebreakers re-break Enigma a month earlier.
Narrative:
Enigma decrypts alert the Allies to the German invasion of Norway. They defeat it completely.
In the gloating over the Norway victory, the break into Enigma leaks to the Germans.
Between Norway and the huge security breach, the Germans postpone the attack on France by three months.
July - with the war in Europe stalemated, FDR decides that the crisis does not require him to continue as President. The Democrats nominate Sen. Burton Wheeler of Idaho, a fiery New Dealer and also fanatic Isolationist.
August - Germany attacks in the West, but the Allies have had three additonal months to prepare. The Germans gain only a limited success by the end of 1940. France is just short of collapse but Germany isn't much better off.
In November - Wheeler narrowly wins election over novice candidate Willkie. Wheeler declares that the U.S. will not aid the Allies, nor even relax the Neutrality Act restrictions on selling arms. He will veto any such moves.
1941
Hitler persuades Mussolini and Sanjurjo to bring Italy and Spain into the war on the German side.
April - Renewed German attacks fail to break Allied forces, but then attacks from Spain and Italy drive into the Allied rear. Allied forces in France collapse. The French government flees to North Africa in June.
June - Axis forces attack French North Africa and Egypt. Allied naval superiority compensates for Axis air and land strength. However U-boats and surface raiders hurt Allied shipping. French colonial and British Empire/Commonwealth troops put up lots of resistance.
August - President Wheeler has said the U.S. will do nothing about Japan and Euro colonies in Asia. Japan now seizes Indochina, Malaya, the Indies, and the South Pacific. (Air raids by unopposed Japanese fleets force Australia and New Zealand to declare neutrality.) The Indian Congress also declares neutrality. British forces hold Ceylon, parts of southern India, what is now Pakistan, and Punjab.
September - French North Africa falls to the Axis. Fighting continues in Libya and northwest Africa.
October - Soviet forces attack west into Germany.
December - German reserves halt Soviet attacks just outside Berlin.
1942
April - Skilful German counterattacks shatter the Soviet forward echelons (still under mediocre post-purge leaders). Assisted by Romania, the Germans drive deep into Soviet territory, capturing Minsk, Riga, and Kiev, with over 1M prisoners.
The stage is now set. The Axis, including Spain, versus the USSR, Britain (minus much of the Empire), and and the French colonial empire. ISTM this war could go on a long time - easily until 1948.
The USSR is not getting any Lend-Lease aid, which OTL represented about 1/3 of its war materiel. There were many categories in which the Soviets were entirely dependent or nearly so on Lend-Lease: locomotives and freight cars, telephone cable, trucks, radios.
Britain is horribly crippled and must fight Japan alone; she can't do much except contain the Axis in Africa and try to bomb Germany.
IMO no. Multiple jet plane projects had already started before the war.