March 23 (Reuters) - Frontier Group is aiming for a valuation of $4.52 billion in its U.S. initial public offering (IPO), according to a regulatory filing by the low-cost carrier on Tuesday, as the industry prepares for a rebound from pandemic-driven travel lows. (Reporting by Noor Zainab Hussain in Bengaluru; Editing by Subhranshu Sahu)