Test

<?php

$apiKey   = 'IWA_U2lUlIQcTz5FhqTzRKQG213IB0Zt9l';
$flightId = '6922fc06b4f4098c1ad0702b';
$apiRoot  = 'https://newsky.app/api/airline-api/';

$flightUrl = $apiRoot . 'flight/' . $flightId;

$ch = curl_init($flightUrl);

curl_setopt_array($ch, [
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_HTTPHEADER => [
        'Authorization: Bearer ' . $apiKey,
        'Accept: application/json',
    ],
]);

$response  = curl_exec($ch);
$httpCode  = curl_getinfo($ch, CURLINFO_HTTP_CODE);
$curlError = curl_error($ch);

curl_close($ch);

if ($curlError) {
    echo "cURL Fehler: " . $curlError . PHP_EOL;
    exit;
}

echo "HTTP-Code: " . $httpCode . PHP_EOL;
echo "Response:\n" . $response . PHP_EOL;

// wenn du direkt [JSON] parsen willst:
$data = json_decode($response, true);
var_dump($data);