I've explored this exact problem and published both a blog post and GitHub project demonstrating how to predict flight delays using machine learning:
https://medium.com/@tarunabagh/delayed-again-how-data-science-predicts-flight-disruptions-before-they-happen-a7dc27327eef
My Medium article, "Delayed Again? How Data Science Predicts Flight Disruptions Before They Happen", walks through:
Data merging across 1.9 M+ flight records, airport metadata & weather.
Exploratory analysis showing weather, carrier, and airport systems drive delays.
Two predictive models: a decision tree and an RNN, with the RNN capturing temporal dependencies in weather and schedule data.
The GitHub repository provides full code for data cleaning, feature engineering, and model training (RNN included):
https://github.com/tarunabagh19/flightdelays_machine-learning