An over engineered solution to (https://www.interviewcake.com/question/python/inflight-entertainment) writen in PHP

InflightEntertainment.php

<?php

class InflightEntertainment
{
    private int $flightLength;
    private array $movieDuration;
    private array $matchedMovies = [];

    public function __construct(int $lengthOfFlight, array $movieDuration)
    {
        $this->flightLength = $lengthOfFlight;
        $this->movieDuration = $movieDuration;
        $this->analyse();
    }

    public function moviesAvailable(): bool
    {
        return count($this->matchedMovies) > 0;
    }

    public function getMatchedMovies(): array
    {
        return array_values($this->matchedMovies);
    }

    private function analyse()
    {
        if (!$this->moviesEmpty()) {
            $this->computeValidChoices();
        }

        return $this;
    }

    private function moviesEmpty(): bool
    {
        return count($this->movieDuration) === 0 || empty($this->movieDuration);
    }

    private function computeValidChoices()
    {
        foreach ($this->movieDuration as $index => $trialDuration) {
            //Am assuming we can't watch the same movie twice.
            // I could have used array_splice but that would reset the indexes which would make the code longer
            $otherMovies = $this->movieDuration;
            unset($otherMovies[$index]);

            foreach ($otherMovies as $index2 => $duration) {
                if ($this->flightLength === $this->sum($duration, $trialDuration)) {
                    $this->addMatchedMovie($index, $index2);
                }
            }
        }

        return $this;
    }

    private function addMatchedMovie(int $index, int $index2)
    {
        $key = $index < $index2 ? "{$index}{$index2}" : "{$index2}{$index}";
        $this->matchedMovies[$key] = [$this->movieDuration[$index], $this->movieDuration[$index2]]; //avoid duplicates
        return $this;
    }

    private function sum(int $value1 = 0, int $value2 = 0): int
    {
        return $value1 + $value2;
    }
}

$movieDuration = [1, 2, 3, 4, 5, 6, 2, 3, 4, 2, 1, 5, 4, 3];
$lengthOfFlight = 6;

$obj = new InflightEntertainment($lengthOfFlight, $movieDuration);

if ($obj->moviesAvailable()) {
    echo "I found movies that match your flight." . PHP_EOL;
    print_r($obj->getMatchedMovies());
} else {
    echo "No movies match your flight.";
}

While inefficient to have nested loops making the solution O(n^2) as opposed to the sweet spot O(n), there is a real chance for 2 or more movies to share exact watch times.