Action Express Racing’s ex-F1 racer lapped Daytona International Speedway’s 3.56-mile road course in 1m35.982s in his Cadillac V-Series.R in warm track conditions for a one-hour session.
Sebastien Bourdais set the early pace in the #01 Chip Ganassi Racing Caddy at 1m36.611s, but Connor De Phillippi beat that mark in the #25 BMW M Hybrid V8 with 1m36.222s.
Pipo Derani then topped the session at 1m36.131s, going 0.091s clear, before team-mate Aitken beat that by dipping under the 1m36s barrier on 1m35.983s.
“We’ve been pretty happy with the car since we set it down at the Roar to be honest,” Aitken told IMSA Radio. “It’s not doing anything unexpected, which is not like last year.”
De Phillippi and Bourdais were second and third respectively, ahead of Richard Westbrook, whose JDC-Miller entry was fastest of the Porsche 963s.
Neel Jani was next up in Proton Competition’s 963 from the factory Penske variants of Nick Tandy and Felipe Nasr.
The Acuras of Louis Deletraz and Ricky Taylor were next up, the #10 Wayne Taylor Racing with Andretti entry beating its #40 sister car. The #24 BMW of Jesse Krohn rounded out the GTP field.
The session was halted with 15 minutes to go, when Lance Willsey crashed his LMP2 Sean Creech Motorsport Ligier into the concrete wall Turn 2.
Mikkel Jensen led the way in LMP2 in his #11 TDS ORECA, lapping in 1m39.078s before a grassy excursion at the Bus Stop (aka: Le Mans) chicane sent him into the pits.
Nobody could beat his time, with Matthieu Vaxiviere getting closest in the #88 Richard Mille AF Corse ORECA, ahead of the similar machines of Ryan Dalziel (Era Motorsport) and Malthe Jakobsen (Crowdstrike by APR).
Thomas Preining led the way in the pro-am #43 Andretti Motorsports Porsche 911, 0.167s quicker than Matteo Cairoli’s Pro class leading #60 Iron Lynx Lamborghini Huracan and Daniel Serra’s Risi Competizione Ferrari 296.
Jens Klingmann was second-fastest in Turner Motorsport’s BMW M4 from Riccardo Agostini (Triarsi Competizione).