Blast from the Past (1999) on Netflix

Plot summary

Calvin Webber is a scientist in the San Fernando Valley who expects a nuclear war with the Soviet Union and digs a hidden shelter under his backyard. The Cuban Missile Crisis sends him and his pregnant wife Helen below. A fighter jet crashes on the house above, so Calvin sets the shelter's time locks to keep the family sealed for 35 years. Helen gives birth to Adam, who is schooled there on the customs of 1962. Above, the suburb slides into decay. When the locks finally release in 1997, Calvin takes the run-down streets for a wasteland and insists they remain below. Supplies run out and Adam climbs out for food, then loses his way. A shopkeeper tries to cheat him, and Eve Rustikov steps in.